feat(frontend): the folders are layers — an import only goes down, a module is reached through its index.ts

`local/layers` (eslint.config.js) resolves every import to its file and refuses one that goes up
(lib/ → components/ui/ → features/ → modules/ → shell/) or that reaches into another module's own
files. A module's index.ts is its public face: the stores, mounted at the root and read app-wide,
which features/ may read too; a page is still opened lazily by import(). Its contract test probes
every edge, and three mutants of the rule (off, no face check, a door for everyone) each turn it red.

Six modules got that face; the shared channel UI (about, tags, tag manager) moved to
features/channel, the filter chips and the saved-views context to features/filters, and the prefs
store's controller type moved next to the store instead of importing it from its own page. The
header's per-module controls and the eagerly loaded rails keep eight inline suppressions, each
naming why: they go when the header gets slots and every rail loads lazily.

`chunkGuard` fails the production build when a lazily imported module lands in a boot chunk (the
entry, the shell, what they import) — e.g. a page re-exported from an index.ts, which makes its
import() a silent no-op. Proved on a build with that mutant; today's build has none.

frontend/chunkGuard.ts

@@ -0,0 +1,40 @@
+import type { Plugin } from "vite";
+import { bootLeaks, type ChunkLike } from "./src/lib/chunkLeaks";
+
+// A lazily imported page, rail, dialog or player must stay out of the chunks loaded at boot (the
+// entry, the shell and what they import): one static import of it on the boot path — a module's
+// index.ts re-exporting it is the easy way — makes its import() a silent no-op. That rule used to be
+// a hope; this makes it a build failure, naming each module and the boot chunk it landed in.
+const SHELL = "src/shell/App.tsx";
+
+export function chunkGuard(): Plugin {
+  return {
+    name: "siftlode-chunk-guard",
+    apply: "build",
+    generateBundle(_options, bundle) {
+      const lazy = new Set(
+        [...this.getModuleIds()].filter(
+          (id) => (this.getModuleInfo(id)?.dynamicImporters.length ?? 0) > 0,
+        ),
+      );
+      const chunks: ChunkLike[] = Object.values(bundle).flatMap((o) =>
+        o.type === "chunk"
+          ? [
+              {
+                fileName: o.fileName,
+                isEntry: o.isEntry,
+                imports: o.imports,
+                moduleIds: o.moduleIds,
+              },
+            ]
+          : [],
+      );
+      const leaks = bootLeaks(chunks, lazy, SHELL);
+      if (leaks.length)
+        this.error(
+          `lazily imported, yet loaded at boot: ${leaks.join(", ")}. ` +
+            "Something on the boot path imports it statically (an index.ts re-export?): import it lazily there too, or not at all.",
+        );
+    },
+  };
+}

frontend/eslint.config.js

@@ -7,6 +7,8 @@ import globals from "globals";
 import eslintComments from "@eslint-community/eslint-plugin-eslint-comments";
 import vitest from "@vitest/eslint-plugin";
 import playwright from "eslint-plugin-playwright";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
 
 // Flat config (ESLint 9). Deliberately NARROW: the high-value rules here are react-hooks' (the
 // hook rules and the React Compiler's diagnostics). The 33 inline `exhaustive-deps` suppressions this
@@ -419,8 +421,89 @@ const glyphLink = {
     };
   },
 };
+// The app's layers (CLAUDE.md "Architecture shape"), bottom up: lib/ → components/ui/ → features/ →
+// modules/ → shell/. An import may go down, never up — with one door: a module's index.ts, its public
+// face, which features/ may read too (the module stores are mounted at the root and read app-wide).
+// Anything else of ANOTHER module is reached through that face, or lazily by import(), which is a
+// chunk boundary and so the way a page is opened. Measured on the import, resolved to its file, so
+// every spelling of a path is the same path. lib/ and ui/ keep their own `no-restricted-imports`
+// blocks below; this rule adds the folders above them.
+const SRC_DIR = path.join(path.dirname(fileURLToPath(import.meta.url)), "src");
+const RANK = { lib: 0, ui: 1, features: 2, modules: 3, shell: 4 };
+function placeOf(abs) {
+  const rel = path.relative(SRC_DIR, abs).split(path.sep).join("/");
+  if (rel.startsWith("..")) return null;
+  const parts = rel.replace(/\.(tsx?|jsx?)$/, "").split("/");
+  const [top, unit] = parts;
+  if (top === "lib") return { layer: "lib" };
+  if (top === "components") return unit === "ui" ? { layer: "ui" } : { layer: "other" };
+  if (top === "features" || top === "modules") {
+    // `modules/plex` and `modules/plex/index` are the unit's public face.
+    const face = parts.length === 2 || (parts.length === 3 && parts[2] === "index");
+    return { layer: top, unit, face };
+  }
+  if (top === "shell") return { layer: "shell" };
+  // main.tsx, watch/, i18n/, content/, design-lab/, the app-wide tests at the root
+  return { layer: "other", top: parts.length === 1 ? "root" : top };
+}
+const layers = {
+  meta: {
+    type: "problem",
+    messages: {
+      up: "{{from}} sits below {{to}}: it may not import from it (`{{spec}}`). Move the shared piece down, or take it as a prop.",
+      face: "`{{spec}}` is one of {{unit}}'s own files: reach another unit through its index.ts (its public face), or lazily with import().",
+    },
+  },
+  create(context) {
+    const file = context.filename;
+    const from = placeOf(file);
+    // The dev-only lab and the app-wide tests at the root look at everything on purpose.
+    const free =
+      !from ||
+      (from.layer === "other" && from.top === "design-lab") ||
+      (from.layer === "other" && from.top === "root" && /\.test(kit)?\.|\.testkit\./.test(file));
+    const check = (node, spec, lazy) => {
+      if (free || typeof spec !== "string" || !spec.startsWith(".")) return;
+      const to = placeOf(path.resolve(path.dirname(file), spec));
+      if (!to || to.layer === "other") return;
+      const fromRank = from.layer === "other" ? 5 : RANK[from.layer];
+      if (
+        to.layer === "shell" &&
+        from.layer !== "shell" &&
+        !(from.layer === "other" && from.top === "root")
+      )
+        return context.report({
+          node,
+          messageId: "up",
+          data: { from: from.layer, to: "shell", spec },
+        });
+      const door = to.layer === "modules" && (to.face || lazy) && from.layer === "features";
+      if (RANK[to.layer] > fromRank && !door)
+        return context.report({
+          node,
+          messageId: "up",
+          data: { from: from.layer, to: to.layer, spec },
+        });
+      const sameUnit = to.layer === from.layer && to.unit === from.unit;
+      if (to.layer === "modules" && !sameUnit && !to.face && !lazy)
+        context.report({ node, messageId: "face", data: { spec, unit: `modules/${to.unit}` } });
+    };
+    return {
+      ImportDeclaration: (n) => check(n.source, n.source.value, false),
+      ExportNamedDeclaration: (n) => n.source && check(n.source, n.source.value, false),
+      ExportAllDeclaration: (n) => check(n.source, n.source.value, false),
+      ImportExpression: (n) => n.source.type === "Literal" && check(n.source, n.source.value, true),
+      TSImportType: (n) => {
+        const lit = n.argument?.literal ?? n.argument;
+        if (lit?.type === "Literal") check(lit, lit.value, false);
+      },
+    };
+  },
+};
+
 const localRules = {
   rules: {
+    layers,
     "glyph-link": glyphLink,
     "sortable-a11y": sortableA11y,
     "jsx-comment-text": jsxCommentText,
@@ -567,6 +650,7 @@ export default tseslint.config(
       "local/literal-a11y-text": "error",
       "local/glyph-link": "error",
       "local/sortable-a11y": "error",
+      "local/layers": "error",
       "react-refresh/only-export-components": ["warn", { allowConstantExport: true }],
       // tsc already enforces these under strict + noUnusedLocals/Parameters — let it own them so a
       // finding is reported once, by one tool, and this config stays about hooks + refresh safety.
@@ -761,7 +845,7 @@ export default tseslint.config(
     // Outside src: the e2e suite and the TypeScript build-tool configs went unlinted — the
     // flat config named only src/**, so `eslint .` skipped them without a word. The same base and
     // typed rules as the app; Node globals, since none of it runs in the browser.
-    files: ["e2e/**/*.ts", "*.config.ts", "reactPlugin.ts", "devOnlyGuard.ts"],
+    files: ["e2e/**/*.ts", "*.config.ts", "reactPlugin.ts", "devOnlyGuard.ts", "chunkGuard.ts"],
     extends: [js.configs.recommended, ...tseslint.configs.recommended],
     languageOptions: {
       ecmaVersion: 2022,

frontend/src/PlaylistEditFailures.dom.test.tsx

@@ -32,7 +32,7 @@ vi.mock("./lib/notifications", async (importOriginal) => ({
 import PlexPlaylistView from "./modules/plex/PlexPlaylistView";
 import AddToPlaylist, { AddToPlaylistAt } from "./features/video/AddToPlaylist";
 import PlexPlaylistAdd from "./features/plexCards/PlexPlaylistAdd";
-import TagManager from "./modules/channels/TagManager";
+import TagManager from "./features/channel/TagManager";
 import { api, HttpError, type PlexCard } from "./lib/api";
 
 beforeAll(() => {

frontend/src/components/ui/README.md

@@ -1,7 +1,7 @@
 # `components/ui/` — the platform layer
 
 Everything in this directory is a **platform component**: generic, reusable, and **domain-free**.
-Everything in `components/` above it is a **module component**: it knows about videos, channels,
+Everything above it — `features/`, `modules/` and `shell/` under `src/` — knows about videos, channels,
 playlists, Plex or downloads.
 
 That boundary is the whole point of this directory. Before E10 S1 these 33 modules sat flat among
@@ -18,9 +18,9 @@ A component belongs here **iff its props and imports name no domain concept**. I
 - generic helpers from `lib/` (`layerStack`, `history`, `columnSort`, `useScrollFade`, …),
 - i18n, React, and third-party UI libraries.
 
-It may **not** import a feature component (`../Feed`) or a domain API slice (`lib/api/*`). This is
-enforced by `no-restricted-imports` in `eslint.config.js` — not by this README, which is only the
-explanation. If a primitive needs domain data, take it as a prop or a render-prop and let the module
+It may **not** import anything from `features/`, `modules/` or `shell/`, or a domain API slice
+(`lib/api/*`). This is enforced in `eslint.config.js` (`no-restricted-imports` and `local/layers`) — not
+by this README, which is only the explanation. If a primitive needs domain data, take it as a prop or a render-prop and let the module
 supply it. The same goes for its words: a primitive translates only from the platform i18n
 namespaces (`common`, `errors`, `datatable`, `keys`, `palette`, `sidebar`, `notifications`, `time` —
 `uiI18n.contract.test.ts`); what a value means where it is used arrives as a prop (`PriorityStepper`'s

frontend/src/components/ui/pressableSelectable.contract.test.ts

@@ -51,7 +51,7 @@ const PLAIN: Record<string, [number, string]> = {
   "modules/scheduler/Scheduler.tsx": [1, "the interval editor trigger"],
   "modules/settings/SettingsPanel.tsx": [1, "a colour swatch"],
   "modules/channels/SyncStatus.tsx": [1, "the status pill trigger"],
-  "modules/channels/TagManager.tsx": [1, "a suggestion in a picker"],
+  "features/channel/TagManager.tsx": [1, "a suggestion in a picker"],
   "modules/files/UploadDialog.tsx": [1, "the drop zone"],
   "features/player/VideoEditor.tsx": [2, "timeline glyphs"],
   "shell/Welcome.tsx": [1, "a screenshot (zoom)"],

frontend/src/features/downloads/DownloadTray.tsx

@@ -37,8 +37,7 @@ import { useLiveQuery } from "../../lib/useLiveQuery";
 import { usePref } from "../../lib/usePref";
 import { ErrorModal } from "./downloadModals";
 import { jobTitle } from "./downloadTitle";
-import { sourceLabel } from "../../modules/files/fileFolders";
-import { useFilesActions } from "../../modules/files/filesContext";
+import { sourceLabel, useFilesActions } from "../../modules/files";
 import { useDownloadActions } from "./useDownloadActions";
 import { type ActionMenuItem } from "../../components/ui/ActionMenu";
 import { setCornerLift } from "../../components/ui/backToTopState";

frontend/src/features/filters/PersonalViewsModal.dom.test.tsx

@@ -63,7 +63,7 @@ const CTX = {
   toggleDefault: vi.fn(async () => {}),
 };
 
-vi.mock("../../modules/feed/savedViewsContext", () => ({
+vi.mock("./savedViewsContext", () => ({
   useSavedViews: () => ({
     ...CTX,
     activeViewId: h.activeViewId,

frontend/src/features/filters/PersonalViewsModal.tsx

@@ -26,9 +26,9 @@ import {
 import Modal from "../../components/ui/Modal";
 import { Button } from "../../components/ui/Button";
 import { IconButton } from "../../components/ui/IconButton";
-import { useSavedViews, asFilters } from "../../modules/feed/savedViewsContext";
+import { useSavedViews, asFilters } from "./savedViewsContext";
 import { useActiveFilters } from "../../lib/useActiveFilters";
-import { buildPlexActiveFilters } from "../../modules/plex/usePlexActiveFilters";
+import { buildPlexActiveFilters } from "../../modules/plex";
 import { useUndoable } from "../../lib/useUndoable";
 import UndoToolbar from "../../components/ui/UndoToolbar";
 import { useSortableA11y, useSortableItem } from "../../components/ui/sortableA11y";

frontend/src/features/filters/SavedViewsPopover.dom.test.tsx

@@ -14,7 +14,7 @@ vi.mock("react-i18next", async (importOriginal) => {
   const actual = await importOriginal<typeof import("react-i18next")>();
   return { ...actual, useTranslation: () => ({ t: (key: string) => key }) };
 });
-vi.mock("../../modules/feed/savedViewsContext", () => ({
+vi.mock("./savedViewsContext", () => ({
   useSavedViews: () => ({ views: [], activeViewId: null, apply: vi.fn(), openModal }),
 }));
 

frontend/src/features/filters/SavedViewsPopover.tsx

@@ -3,7 +3,7 @@ import { useTranslation } from "react-i18next";
 import { Settings2 } from "lucide-react";
 import { PopoverItem, PopoverSurface } from "../../components/ui/AnchoredPopover";
 import { closeThenAct, useAnchoredPopover } from "../../components/ui/anchoredPopoverHooks";
-import { useSavedViews } from "../../modules/feed/savedViewsContext";
+import { useSavedViews } from "./savedViewsContext";
 import { IconButton } from "../../components/ui/IconButton";
 import { MenuCheck } from "../../components/ui/MenuCheck";
 import { SURFACE } from "../../components/ui/surfaces";

frontend/src/features/filters/SelectedViewChip.tsx

@@ -1,7 +1,7 @@
 import { useTranslation } from "react-i18next";
 import { Bookmark } from "lucide-react";
 import SavedViewsPopover from "./SavedViewsPopover";
-import { useSavedViews } from "../../modules/feed/savedViewsContext";
+import { useSavedViews } from "./savedViewsContext";
 
 // The active personal view, shown as the leading pill before the active-filter chip row. Styled like
 // the toolbar's FilterSelect pills; a warn-coloured dot appears when the live filters have diverged

frontend/src/features/prefs/PrefsProvider.tsx

@@ -24,8 +24,7 @@ import {
 } from "../../lib/notifications";
 import { hintsEnabled, setHintsEnabled } from "../../lib/hints";
 import { getAccountRaw, LS, setAccountRaw } from "../../lib/storage";
-import type { PrefsController } from "../../modules/settings/SettingsPanel";
-import { PrefsContext } from "./prefsContext";
+import { PrefsContext, type PrefsController } from "./prefsContext";
 
 const PERF_KEY = LS.perfMode;
 

frontend/src/features/prefs/prefsContext.ts

@@ -1,11 +1,29 @@
 import { createContext, useContext } from "react";
-import { DEFAULT_THEME } from "../../lib/theme";
-import { getNotifSettings } from "../../lib/notifications";
-import type { PrefsController } from "../../modules/settings/SettingsPanel";
+import { DEFAULT_THEME, type ThemePrefs } from "../../lib/theme";
+import { getNotifSettings, type NotifSettings } from "../../lib/notifications";
+import type { SaveState } from "../../components/ui/DraftSaveBar";
 
 // The Settings-page preferences context + hook, split out of PrefsProvider so that file exports only
 // components (Fast Refresh).
 
+// The Settings page edits server-persisted preferences. Each change applies locally for instant
+// preview AND auto-saves (debounced) — no draft, no Save button; a small indicator flashes the
+// outcome. PrefsProvider owns the state + the save; this controller is how the page reads/writes it.
+// It lives with the store rather than with the page, so the store does not depend on its page.
+export interface PrefsController {
+  theme: ThemePrefs;
+  setTheme: (t: ThemePrefs) => void;
+  perf: boolean;
+  setPerf: (v: boolean) => void;
+  hints: boolean;
+  setHints: (v: boolean) => void;
+  railLabels: boolean;
+  setRailLabels: (v: boolean) => void;
+  notif: NotifSettings;
+  setNotif: (n: NotifSettings) => void;
+  saveState: SaveState;
+}
+
 export const PrefsContext = createContext<PrefsController>({
   theme: DEFAULT_THEME,
   setTheme: () => {},

frontend/src/lib/chunkLeaks.test.ts

@@ -0,0 +1,43 @@
+import { describe, expect, it } from "vitest";
+import { bootLeaks, type ChunkLike } from "./chunkLeaks";
+
+const APP = "/r/src/shell/App.tsx";
+const chunk = (fileName: string, moduleIds: string[], imports: string[] = [], isEntry = false) =>
+  ({ fileName, moduleIds, imports, isEntry }) satisfies ChunkLike;
+
+describe("a lazily imported module", () => {
+  const lazy = new Set([APP, "/r/src/modules/plex/PlexBrowse.tsx"]);
+
+  it("is a leak in the entry chunk, in a chunk the entry imports, or in the App chunk", () => {
+    const P = "/r/src/modules/plex/PlexBrowse.tsx";
+    for (const chunks of [
+      [chunk("index.js", ["/r/src/main.tsx", P], [], true)],
+      [chunk("index.js", ["/r/src/main.tsx"], ["shared.js"], true), chunk("shared.js", [P])],
+      [chunk("index.js", ["/r/src/main.tsx"], [], true), chunk("App.js", [APP, P])],
+      [
+        chunk("index.js", ["/r/src/main.tsx"], [], true),
+        chunk("App.js", [APP], ["s.js"]),
+        chunk("s.js", [P]),
+      ],
+    ])
+      expect(bootLeaks(chunks, lazy, "src/shell/App.tsx")).toEqual([
+        `${P} (${chunks[chunks.length - 1]!.fileName})`,
+      ]);
+  });
+
+  it("is not a leak in its own chunk, or in one only another lazy chunk loads — and App itself is lazy by design", () => {
+    const chunks = [
+      chunk("index.js", ["/r/src/main.tsx"], ["react.js"], true),
+      chunk("react.js", ["/r/node_modules/react/index.js"]),
+      chunk("App.js", [APP], ["react.js"]),
+      chunk("PlexBrowse.js", ["/r/src/modules/plex/PlexBrowse.tsx"], ["react.js"]),
+    ];
+    expect(bootLeaks(chunks, lazy, "src/shell/App.tsx")).toEqual([]);
+  });
+
+  it("is checked on Windows paths too", () => {
+    const win = "D:\\r\\src\\modules\\plex\\PlexBrowse.tsx";
+    const chunks = [chunk("index.js", ["D:\\r\\src\\main.tsx", win], [], true)];
+    expect(bootLeaks(chunks, new Set([win]), "src/shell/App.tsx")).toHaveLength(1);
+  });
+});

frontend/src/lib/chunkLeaks.ts

@@ -0,0 +1,40 @@
+// Which lazily imported modules a production build loads at boot anyway — the logic behind the
+// chunkGuard build plugin (frontend/chunkGuard.ts), kept free of Vite so a unit test can drive it.
+//
+// A page, a rail, a dialog or a player is imported with import()/lazy() so it is fetched only when it
+// is opened. Rollup honours that only while nothing on the boot path imports the same module
+// statically: one static import — a re-export from a module's index.ts is the easy way to add one —
+// and the module joins a boot chunk, the import() becomes a no-op, and nothing says so. The boot path
+// is the entry chunks and what they import, plus the shell (App, itself loaded lazily but fetched
+// at boot alongside the identity probe) and what it imports.
+
+export interface ChunkLike {
+  fileName: string;
+  isEntry: boolean;
+  /** The chunks this one imports statically. */
+  imports: string[];
+  moduleIds: string[];
+}
+
+const posix = (id: string) => id.split("\\").join("/");
+
+/** Every lazily imported module (`lazy`: module ids) that sits in a boot chunk, as "id (chunk)". The
+ *  shell's own module (`shell`, a path under the project, e.g. "src/shell/App.tsx") is exempt: it is
+ *  lazy so that the public pages never load it, and its chunk is the shell. */
+export function bootLeaks(chunks: ChunkLike[], lazy: Set<string>, shell: string): string[] {
+  const byName = new Map(chunks.map((c) => [c.fileName, c]));
+  const isShell = (id: string) => posix(id).endsWith(`/${shell}`);
+  const roots = chunks.filter((c) => c.isEntry || c.moduleIds.some(isShell));
+  const boot = new Set<ChunkLike>();
+  const visit = (c: ChunkLike | undefined) => {
+    if (!c || boot.has(c)) return;
+    boot.add(c);
+    c.imports.forEach((name) => visit(byName.get(name)));
+  };
+  roots.forEach(visit);
+  const leaks: string[] = [];
+  for (const c of boot)
+    for (const id of c.moduleIds)
+      if (lazy.has(id) && !isShell(id)) leaks.push(`${posix(id)} (${c.fileName})`);
+  return leaks.sort();
+}

frontend/src/lib/gates.contract.test.ts

@@ -471,6 +471,8 @@ describe("the gate register (docs/gates.md)", () => {
       "vitest.config.ts",
       "reactPlugin.ts",
       "devOnlyGuard.ts",
+      "chunkGuard.ts",
+      "src/lib/chunkLeaks.ts",
       "playwright.config.ts",
       "postcss.config.js",
     ],

frontend/src/lib/gates.snapshot.json

@@ -35,6 +35,7 @@
         "local/glyph-link",
         "local/input-primitive",
         "local/jsx-comment-text",
+        "local/layers",
         "local/literal-a11y-text",
         "local/locale-format",
         "local/sortable-a11y",
@@ -117,6 +118,7 @@
         "local/glyph-link",
         "local/input-primitive",
         "local/jsx-comment-text",
+        "local/layers",
         "local/literal-a11y-text",
         "local/locale-format",
         "local/sortable-a11y",
@@ -642,6 +644,7 @@
         "local/glyph-link": [2],
         "local/input-primitive": [2],
         "local/jsx-comment-text": [2],
+        "local/layers": [2],
         "local/literal-a11y-text": [2],
         "local/locale-format": [2],
         "local/sortable-a11y": [2],
@@ -1055,6 +1058,7 @@
         "local/glyph-link",
         "local/input-primitive",
         "local/jsx-comment-text",
+        "local/layers",
         "local/literal-a11y-text",
         "local/locale-format",
         "local/sortable-a11y",

frontend/src/lib/layers.contract.test.ts

@@ -0,0 +1,91 @@
+import { describe, expect, it } from "vitest";
+
+import { eslint } from "./lintProbe.testkit";
+
+// The layer rule (local/layers in eslint.config.js) is what makes the folders a structure rather
+// than a filing habit: lib/ → components/ui/ → features/ → modules/ → shell/, an import only goes
+// down, and a module's own files are reached from outside only through its index.ts or lazily. A
+// rule that matched nothing would look exactly like a clean codebase, so each edge is probed here.
+async function refused(source: string, filePath: string): Promise<string[]> {
+  const [result] = await eslint.lintText(source, { filePath });
+  return (result?.messages ?? []).filter((m) => m.ruleId === "local/layers").map((m) => m.message);
+}
+const imp = (...specs: string[]) =>
+  specs.map((s, i) => `import x${i} from "${s}";\n`).join("") +
+  `export default [${specs.map((_, i) => `x${i}`).join(", ")}];\n`;
+
+const IN_FEED = "src/modules/feed/__probe.tsx";
+const IN_FEATURE = "src/features/video/__probe.tsx";
+
+describe("a module", () => {
+  it("reaches another module only through its index.ts", async () => {
+    expect(await refused(imp("../plex/PlexBrowse"), IN_FEED)).toHaveLength(1);
+    expect(await refused(imp("../plex", "../plex/index"), IN_FEED)).toEqual([]);
+  });
+
+  it("by every spelling: a type, a re-export, a type-only import", async () => {
+    const src =
+      'import type { P } from "../plex/plexContext";\n' +
+      'export { usePlex } from "../plex/plexContext";\n' +
+      'export * from "../channels/channelsContext";\n' +
+      "export type Q = P;\n";
+    expect(await refused(src, IN_FEED)).toHaveLength(3);
+  });
+
+  it("may open another module's page lazily, and use its own files and anything below", async () => {
+    const src =
+      'const P = () => import("../plex/PlexBrowse");\n' +
+      'import F from "./Feed";\nimport V from "../../features/video/VideoCard";\n' +
+      'import B from "../../components/ui/Button";\nimport { qk } from "../../lib/queryKeys";\n' +
+      "export default [P, F, V, B, qk];\n";
+    expect(await refused(src, IN_FEED)).toEqual([]);
+  });
+
+  it("never imports the shell", async () => {
+    expect(await refused(imp("../../shell/Header"), IN_FEED)).toHaveLength(1);
+  });
+});
+
+describe("a feature", () => {
+  it("reads a module only through its face, and never the shell", async () => {
+    expect(await refused(imp("../../modules/plex"), IN_FEATURE)).toEqual([]);
+    const up = await refused(imp("../../modules/plex/plexContext", "../../shell/App"), IN_FEATURE);
+    expect(up).toHaveLength(2);
+    expect(up.every((m) => m.includes("sits below"))).toBe(true);
+  });
+
+  it("uses other features freely", async () => {
+    expect(await refused(imp("../player/ClipPanel", "../filters/SearchBar"), IN_FEATURE)).toEqual(
+      [],
+    );
+  });
+});
+
+describe("the platform and lib layers", () => {
+  it("import nothing above them — not even a module's face", async () => {
+    const ui = await refused(
+      imp("../../features/video/VideoCard", "../../modules/feed", "../../shell/App"),
+      "src/components/ui/__layers_probe.tsx",
+    );
+    expect(ui).toHaveLength(3);
+    const lib = await refused(
+      imp("../features/navigation/navigationContext", "../modules/feed", "../shell/App"),
+      "src/lib/__layers_probe.ts",
+    );
+    expect(lib).toHaveLength(3);
+  });
+});
+
+describe("the shell and the entry", () => {
+  it("reach a module through its face, or lazily", async () => {
+    const src =
+      imp("../modules/feed/Feed", "../modules/feed") +
+      'export const L = () => import("../modules/feed/Feed");\n';
+    expect(await refused(src, "src/shell/__layers_probe.tsx")).toHaveLength(1);
+  });
+
+  it("only the root entry mounts the shell", async () => {
+    expect(await refused(imp("./shell/App"), "src/__layers_probe.tsx")).toEqual([]);
+    expect(await refused(imp("./modules/feed/Feed"), "src/__layers_probe.tsx")).toHaveLength(1);
+  });
+});

frontend/src/lib/lintProbe.testkit.ts

@@ -15,8 +15,11 @@ const FRONTEND = fileURLToPath(new URL("../../", import.meta.url));
 // file no tsconfig includes, so those names are let into TypeScript's default project here — the
 // probe still runs the real config, typed rules included, rather than a copy with them switched off.
 const PROBE_FILES = [
+  "src/__*probe.tsx",
   "src/*/__*probe.ts",
   "src/*/__*probe.tsx",
+  // a file inside one module or feature (src/modules/feed/…), for the layer rule
+  "src/*/*/__*probe.tsx",
   "src/components/ui/__*probe.tsx",
   "src/lib/api/__*probe.ts",
   "src/components/Button.tsx",

frontend/src/main.tsx

@@ -7,14 +7,11 @@ import ErrorBoundary from "./shell/ErrorBoundary";
 import { ConfirmProvider } from "./components/ui/ConfirmProvider";
 import BootGate, { BootScreen } from "./shell/BootGate";
 import { NavigationProvider } from "./features/navigation/NavigationProvider";
-import { FeedFiltersProvider } from "./modules/feed/FeedFiltersProvider";
-import { SavedViewsProvider } from "./modules/feed/SavedViewsProvider";
-import { PlaylistsProvider } from "./modules/playlists/PlaylistsProvider";
-import { FilesProvider } from "./modules/files/FilesProvider";
-import { PlexProvider } from "./modules/plex/PlexProvider";
-import { PlexViewBridge } from "./modules/plex/PlexViewBridge";
-import { ChannelsProvider } from "./modules/channels/ChannelsProvider";
-import { FeedViewProvider } from "./modules/feed/FeedViewProvider";
+import { FeedFiltersProvider, FeedViewProvider, SavedViewsProvider } from "./modules/feed";
+import { PlaylistsProvider } from "./modules/playlists";
+import { FilesProvider } from "./modules/files";
+import { PlexProvider, PlexViewBridge } from "./modules/plex";
+import { ChannelsProvider } from "./modules/channels";
 import { PrefsProvider } from "./features/prefs/PrefsProvider";
 import { WizardProvider } from "./features/wizard/WizardProvider";
 import "./i18n";

frontend/src/modules/activity/index.ts

@@ -0,0 +1,2 @@
+// The activity page's public face: what another unit may use of it.
+export { StatusDot, type DotKey } from "./RunStatusDot";

frontend/src/modules/channels/AboutCell.tsx

@@ -2,7 +2,7 @@ import { useState } from "react";
 import { useQuery } from "@tanstack/react-query";
 import { qk } from "../../lib/queryKeys";
 import { api } from "../../lib/api";
-import ChannelAboutContent from "./ChannelAbout";
+import ChannelAboutContent from "../../features/channel/ChannelAbout";
 import { PopoverSurface } from "../../components/ui/AnchoredPopover";
 import { useAnchoredPopover } from "../../components/ui/anchoredPopoverHooks";
 import { SURFACE } from "../../components/ui/surfaces";

frontend/src/modules/channels/Channels.tsx

@@ -33,14 +33,14 @@ import { useChannelActions } from "./useChannelActions";
 import { useContextMenu } from "../../components/ui/useContextMenu";
 import { LoadingState, StateMessage } from "../../components/ui/QueryState";
 import { useChannelTagActions } from "../../lib/useChannelTagActions";
-import { useTagSuggestions } from "./useTagSuggestions";
+import { useTagSuggestions } from "../../features/channel/useTagSuggestions";
 import { useChannelPriority } from "../../lib/useChannelPriority";
 import { placeByPriority } from "../../lib/channelOrder";
 import { focusNavItem } from "../../lib/listNav";
 import ViewSwitcher, { type ViewOption } from "../../components/ui/ViewSwitcher";
 import ColumnSortControl from "../../components/ui/ColumnSortControl";
 import FilterChipGroup from "../../components/ui/FilterChipGroup";
-import TagFilterChips from "../feed/TagFilterChips";
+import TagFilterChips from "../../features/filters/TagFilterChips";
 import ActionMenu, { type ActionMenuItem } from "../../components/ui/ActionMenu";
 import ChannelStatsPopover from "./ChannelStatsPopover";
 import Pager from "../../components/ui/Pager";
@@ -57,10 +57,10 @@ import { menuGroups } from "../../components/ui/menuGroups";
 import { choiceSubmenu, sortSubmenu } from "../../components/ui/pageMenuItems";
 import { optionsFromColumns } from "../../lib/sortOptions";
 import ChannelDiscovery from "./ChannelDiscovery";
-import TagManager from "./TagManager";
+import TagManager from "../../features/channel/TagManager";
 import { useChannelLayout, useChannels, useChannelsActions } from "./channelsContext";
 import { useNavigationActions } from "../../features/navigation/navigationContext";
-import { useFeedFilters, useFeedFiltersActions } from "../feed/feedFiltersContext";
+import { useFeedFilters, useFeedFiltersActions } from "../feed";
 import { useWizard } from "../../features/wizard/wizardContext";
 import { useMe } from "../../lib/useMe";
 import { useTags } from "../../lib/useTags";

frontend/src/modules/channels/channelColumns.tsx

@@ -7,11 +7,11 @@ import type { Column } from "../../components/ui/DataTable";
 import { PriorityStepper } from "../../components/ui/PriorityStepper";
 import ChannelLink from "./ChannelLink";
 import AboutCell from "./AboutCell";
-import { ChannelTagsControl, type SuggestedTag } from "./ChannelTags";
+import { ChannelTagsControl, type SuggestedTag } from "../../features/channel/ChannelTags";
 import { StoredCell } from "./channelCells";
 import { isFullySynced } from "./channelSync";
 import { RelativeTime } from "../../components/ui/RelativeTime";
-import type { FilterChip } from "../feed/TagFilterChips";
+import type { FilterChip } from "../../features/filters/TagFilterChips";
 
 /** The shared "subscribers" DataTable column (right-aligned, sortable, em-dash for null) — identical
  * in the Channels manager and the ChannelDiscovery table, which show subscriber counts on different

frontend/src/modules/channels/index.ts

@@ -0,0 +1,3 @@
+// The channel manager's public face: its store, mounted at the root and read app-wide.
+export { ChannelsProvider } from "./ChannelsProvider";
+export { useChannels, useChannelsActions } from "./channelsContext";

frontend/src/modules/feed/ChannelPage.backfill.dom.test.tsx

@@ -24,7 +24,7 @@ vi.mock("./feedFiltersContext", () => ({
   useFeedFilters: () => ({ includeNormal: true, includeShorts: false, includeLive: false }),
 }));
 vi.mock("./Feed", () => ({ default: () => null }));
-vi.mock("../channels/ChannelAbout", () => ({ default: () => null }));
+vi.mock("../../features/channel/ChannelAbout", () => ({ default: () => null }));
 
 import ChannelPage from "./ChannelPage";
 import { api, type ChannelDetail, type FeedFilters, type Me } from "../../lib/api";

frontend/src/modules/feed/ChannelPage.banner.dom.test.tsx

@@ -22,7 +22,7 @@ vi.mock("./feedFiltersContext", () => ({
   useFeedFilters: () => ({ includeNormal: true, includeShorts: false, includeLive: false }),
 }));
 vi.mock("./Feed", () => ({ default: () => null }));
-vi.mock("../channels/ChannelAbout", () => ({ default: () => null }));
+vi.mock("../../features/channel/ChannelAbout", () => ({ default: () => null }));
 // The page's chrome portals into the shell's fixed toolbar band, which this test has no shell for.
 vi.mock("../../components/ui/PageShell", async (importOriginal) => ({
   ...(await importOriginal<typeof import("../../components/ui/PageShell")>()),

frontend/src/modules/feed/ChannelPage.busyFocus.dom.test.tsx

@@ -22,7 +22,7 @@ vi.mock("./feedFiltersContext", () => ({
   useFeedFilters: () => ({ includeNormal: true, includeShorts: false, includeLive: false }),
 }));
 vi.mock("./Feed", () => ({ default: () => null }));
-vi.mock("../channels/ChannelAbout", () => ({ default: () => null }));
+vi.mock("../../features/channel/ChannelAbout", () => ({ default: () => null }));
 // The page's chrome portals into the shell's fixed toolbar band, which this test has no shell for.
 vi.mock("../../components/ui/PageShell", async (importOriginal) => ({
   ...(await importOriginal<typeof import("../../components/ui/PageShell")>()),

frontend/src/modules/feed/ChannelPage.fold.dom.test.tsx

@@ -21,7 +21,7 @@ vi.mock("./feedFiltersContext", () => ({
   useFeedFilters: () => ({ includeNormal: true, includeShorts: false, includeLive: false }),
 }));
 vi.mock("./Feed", () => ({ default: () => null }));
-vi.mock("../channels/ChannelAbout", () => ({ default: () => null }));
+vi.mock("../../features/channel/ChannelAbout", () => ({ default: () => null }));
 vi.mock("../../components/ui/PageShell", async (importOriginal) => ({
   ...(await importOriginal<typeof import("../../components/ui/PageShell")>()),
   PageToolbar: ({ children }: { children?: ReactNode }) => <>{children}</>,

frontend/src/modules/feed/ChannelPage.tsx

@@ -26,7 +26,7 @@ import Tabs from "../../components/ui/Tabs";
 import { useTabPanel } from "../../components/ui/tabPanel";
 import { useScrollFold } from "../../components/ui/scrollFold";
 import Feed from "./Feed";
-import ChannelAboutContent from "../channels/ChannelAbout";
+import ChannelAboutContent from "../../features/channel/ChannelAbout";
 import { PageToolbar } from "../../components/ui/PageShell";
 import { PageToolbarSlot } from "../../components/ui/pageToolbarSlot";
 import { useFeedFilters } from "./feedFiltersContext";
@@ -46,7 +46,7 @@ import {
 } from "../../lib/api";
 import type { FeedView } from "../../lib/feedView";
 import { channelYouTubeUrl, formatDate, formatCompact } from "../../lib/format";
-import { ChannelTagsControl } from "../channels/ChannelTags";
+import { ChannelTagsControl } from "../../features/channel/ChannelTags";
 import { useChannelTagActions } from "../../lib/useChannelTagActions";
 import { Button } from "../../components/ui/Button";
 import { IconButton } from "../../components/ui/IconButton";

frontend/src/modules/feed/ChannelPage.watchState.dom.test.tsx

@@ -28,7 +28,7 @@ vi.mock("./Feed", () => ({
     return null;
   },
 }));
-vi.mock("../channels/ChannelAbout", () => ({ default: () => null }));
+vi.mock("../../features/channel/ChannelAbout", () => ({ default: () => null }));
 vi.mock("../../components/ui/PageShell", async (importOriginal) => ({
   ...(await importOriginal<typeof import("../../components/ui/PageShell")>()),
   PageToolbar: ({ children }: { children?: ReactNode }) => <>{children}</>,

frontend/src/modules/feed/SavedViewsProvider.dom.test.tsx

@@ -45,7 +45,7 @@ vi.mock("../plex/plexContext", () => ({
 vi.mock("../../components/ui/confirmContext", () => ({ useConfirm: () => async () => true }));
 
 import { SavedViewsProvider } from "./SavedViewsProvider";
-import { useSavedViews } from "./savedViewsContext";
+import { useSavedViews } from "../../features/filters/savedViewsContext";
 import { api, type SavedView } from "../../lib/api";
 import { claimLocalData, LS } from "../../lib/storage";
 import { qk } from "../../lib/queryKeys";

frontend/src/modules/feed/SavedViewsProvider.tsx

@@ -17,13 +17,13 @@ import { LS, ownKey } from "../../lib/storage";
 import { useConfirm } from "../../components/ui/confirmContext";
 import { useNavigation } from "../../features/navigation/navigationContext";
 import { useFeedFilters, useFeedFiltersActions } from "./feedFiltersContext";
-import { usePlex, usePlexActions } from "../plex/plexContext";
+import { usePlex, usePlexActions } from "../plex";
 import {
   asFilters,
   SavedViewsCtx,
   type SavedViewsContext,
   type ViewSource,
-} from "./savedViewsContext";
+} from "../../features/filters/savedViewsContext";
 
 // Saved "smart views" now serve TWO modules — the feed and Plex — keyed by `source`. This one provider
 // switches which module it operates on by the active page (both filter providers are global, so it can

frontend/src/modules/feed/Sidebar.tsx

@@ -7,9 +7,9 @@ import { api, NO_TAG_SENTINEL, type FeedFilters, type Tag, type TagCategory } fr
 import { defaultLayout, type PanelLayout } from "../../lib/panelLayout";
 import { useDebounced } from "../../lib/useDebounced";
 import { useActiveFilters } from "../../lib/useActiveFilters";
-import TagManager from "../channels/TagManager";
+import TagManager from "../../features/channel/TagManager";
 import SavedViewsPopover from "../../features/filters/SavedViewsPopover";
-import { useSavedViews } from "./savedViewsContext";
+import { useSavedViews } from "../../features/filters/savedViewsContext";
 import FilterRail from "../../components/ui/FilterRail";
 import { type PanelItem } from "../../components/ui/PanelGroups";
 import { type MediaSourceKind } from "../../lib/mediaSource";
@@ -20,7 +20,7 @@ import YearFilter from "./YearFilter";
 import Combobox from "../../components/ui/Combobox";
 import MatchToggle from "../../components/ui/MatchToggle";
 import { useFeedFilters, useFeedFiltersActions } from "./feedFiltersContext";
-import { useChannelsActions } from "../channels/channelsContext";
+import { useChannelsActions } from "../channels";
 import { useTags } from "../../lib/useTags";
 import { compareText } from "../../lib/collate";
 

frontend/src/modules/feed/index.ts

@@ -0,0 +1,6 @@
+// The feed's public face: its stores (filters, view, saved views), mounted at the root and read app-wide.
+export { FeedFiltersProvider } from "./FeedFiltersProvider";
+export { FeedViewProvider } from "./FeedViewProvider";
+export { SavedViewsProvider } from "./SavedViewsProvider";
+export { useFeedFilters, useFeedFiltersActions } from "./feedFiltersContext";
+export { useFeedView, useFeedViewActions } from "./feedViewContext";

frontend/src/modules/feed/modulePages.tsx

@@ -4,7 +4,7 @@ import { useFeedFilters, useFeedFiltersActions } from "./feedFiltersContext";
 import { useFeedView, useFeedViewActions } from "./feedViewContext";
 import { useNavigation, useNavigationActions } from "../../features/navigation/navigationContext";
 import PersonalViewsModal from "../../features/filters/PersonalViewsModal";
-import { useSavedViews } from "./savedViewsContext";
+import { useSavedViews } from "../../features/filters/savedViewsContext";
 
 // The two module-registry pages that need per-render wiring (see moduleRegistry), split out of it so
 // that file exports only data and this one only components (Fast Refresh). Their lazy chunks are

frontend/src/modules/files/LinkBox.intake.dom.test.tsx

@@ -11,7 +11,7 @@ vi.mock("react-i18next", async (importOriginal) => ({
   ...(await importOriginal<typeof import("react-i18next")>()),
   useTranslation: () => ({ i18n: { language: "en" }, t: (key: string) => key }),
 }));
-vi.mock("./DownloadDialog", () => ({
+vi.mock("../../features/downloads/DownloadDialog", () => ({
   default: ({ source, onClose }: { source: string; onClose: () => void }) => (
     <div role="dialog" aria-label="download">
       {source}
@@ -20,8 +20,8 @@ vi.mock("./DownloadDialog", () => ({
   ),
 }));
 
-import DownloadIntake from "./DownloadIntake";
-import { LinkBox } from "../../modules/files/LinkBox";
+import DownloadIntake from "../../features/downloads/DownloadIntake";
+import { LinkBox } from "./LinkBox";
 import { clearPendingDownload, requestLinkBox } from "../../lib/downloadIntake";
 import { ensureNavId } from "../../lib/history";
 import { pushLayer, removeLayer } from "../../lib/layerStack";

frontend/src/modules/files/index.ts

@@ -0,0 +1,4 @@
+// The Files page's public face: its store, mounted at the root, and how a folder is named and pictured.
+export { FilesProvider } from "./FilesProvider";
+export { useFiles, useFilesActions } from "./filesContext";
+export { folderIcon, folderLabel, sourceLabel, takesUploads } from "./fileFolders";

frontend/src/modules/home/Home.tsx

@@ -55,9 +55,9 @@ import VideoCard, { VideoHoverActions } from "../../features/video/VideoCard";
 import { useVideoActions } from "../../features/video/useVideoActions";
 import { usePlexCardActions } from "../../features/plexCards/usePlexCardActions";
 import { PlexHoverBar, PlexPosterCard } from "../../features/plexCards/plexCards";
-import { usePlaylistsActions } from "../playlists/playlistsContext";
+import { usePlaylistsActions } from "../playlists";
 import { useNavigationActions } from "../../features/navigation/navigationContext";
-import { usePlexActions } from "../plex/plexContext";
+import { usePlexActions } from "../plex";
 import { navItemAttrs } from "../../lib/listNav";
 import { Pressable } from "../../components/ui/Pressable";
 import { SURFACE } from "../../components/ui/surfaces";

frontend/src/modules/notifications/NotificationsPanel.tsx

@@ -47,9 +47,9 @@ import { PageToolbar } from "../../components/ui/PageShell";
 import { PageMenu } from "../../components/ui/PageMenu";
 import { LoadingState, StateMessage } from "../../components/ui/QueryState";
 import { useNavigationActions } from "../../features/navigation/navigationContext";
-import { useFilesActions } from "../files/filesContext";
-import { useChannelsActions } from "../channels/channelsContext";
-import { useFeedFilters, useFeedFiltersActions } from "../feed/feedFiltersContext";
+import { useFilesActions } from "../files";
+import { useChannelsActions } from "../channels";
+import { useFeedFilters, useFeedFiltersActions } from "../feed";
 import { SURFACE } from "../../components/ui/surfaces";
 import { SectionLabel } from "../../components/ui/Headings";
 import NavGrid from "../../components/ui/NavGrid";

frontend/src/modules/playlists/index.ts

@@ -0,0 +1,3 @@
+// The playlists page's public face: its store, mounted at the root and read app-wide.
+export { PlaylistsProvider } from "./PlaylistsProvider";
+export { usePlaylists, usePlaylistsActions } from "./playlistsContext";

frontend/src/modules/plex/PlexSidebar.tsx

@@ -18,7 +18,7 @@ import FilterChipGroup from "../../components/ui/FilterChipGroup";
 import Combobox, { type ComboboxOption } from "../../components/ui/Combobox";
 import SavedViewsPopover from "../../features/filters/SavedViewsPopover";
 import PersonalViewsModal from "../../features/filters/PersonalViewsModal";
-import { useSavedViews } from "../feed/savedViewsContext";
+import { useSavedViews } from "../../features/filters/savedViewsContext";
 import { usePlex, usePlexActions } from "./plexContext";
 import { DismissibleChip } from "../../components/ui/Chip";
 import { Input } from "../../components/ui/Input";

frontend/src/modules/plex/index.ts

@@ -0,0 +1,5 @@
+// The Plex module's public face: its store, mounted at the root and read app-wide, and how its filters read as chips.
+export { PlexProvider } from "./PlexProvider";
+export { PlexViewBridge } from "./PlexViewBridge";
+export { usePlex, usePlexActions } from "./plexContext";
+export { buildPlexActiveFilters } from "./usePlexActiveFilters";

frontend/src/modules/scheduler/Scheduler.tsx

@@ -44,7 +44,7 @@ import { ContextMenu } from "../../components/ui/ContextMenu";
 import { MoreButton } from "../../components/ui/MoreButton";
 import { type ActionMenuItem } from "../../components/ui/ActionMenu";
 import { jobFailureText, jobResultText } from "../../lib/jobResult";
-import { StatusDot, type DotKey } from "../activity/RunStatusDot";
+import { StatusDot, type DotKey } from "../activity";
 import { useNavigationActions } from "../../features/navigation/navigationContext";
 import { urlWithParams } from "../../lib/urlState";
 

frontend/src/modules/settings/ApiTokens.tsx

@@ -18,7 +18,7 @@ import { compareText } from "../../lib/collate";
 import { formatDate } from "../../lib/format";
 import { navItemAttrs } from "../../lib/listNav";
 import { useConfirm } from "../../components/ui/confirmContext";
-import { folderIcon, folderLabel, takesUploads } from "../files/fileFolders";
+import { folderIcon, folderLabel, takesUploads } from "../files";
 import { type ActionMenuItem } from "../../components/ui/ActionMenu";
 import { Badge } from "../../components/ui/Badge";
 import { Button } from "../../components/ui/Button";

frontend/src/modules/settings/SettingsPanel.tsx

@@ -20,7 +20,7 @@ import { DownloadFormats } from "./ProfileEditor";
 import DiagnosticsSettings from "./DiagnosticsSettings";
 import ApiTokens from "./ApiTokens";
 import { type SettingsTabId } from "../../lib/settingsTab";
-import { SCHEMES, type Scheme, type ThemePrefs } from "../../lib/theme";
+import { SCHEMES, type Scheme } from "../../lib/theme";
 import { api, HttpError, type Me } from "../../lib/api";
 import { displayName, roleKey } from "../../lib/api/account";
 import { notifyActionError } from "../../lib/actionErrors";
@@ -40,7 +40,7 @@ import {
   START_ON_HOME_PREF,
 } from "../../features/navigation/navigationInit";
 import { usePref } from "../../lib/usePref";
-import { usePrefs } from "../../features/prefs/prefsContext";
+import { usePrefs, type PrefsController } from "../../features/prefs/prefsContext";
 import Tabs from "../../components/ui/Tabs";
 import { useTabPanel } from "../../components/ui/tabPanel";
 import { useMe } from "../../lib/useMe";
@@ -49,25 +49,6 @@ import { Slider } from "../../components/ui/NativeControls";
 import { Input, Textarea } from "../../components/ui/Input";
 import { SURFACE } from "../../components/ui/surfaces";
 
-// The Settings page edits server-persisted preferences. Each change applies locally for instant
-// preview AND auto-saves (debounced) — no draft, no Save button; a small indicator flashes the
-// outcome. PrefsProvider owns the state + the save; this controller
-// is how the panel reads/writes it.
-export type PrefsSaveState = SaveState;
-export interface PrefsController {
-  theme: ThemePrefs;
-  setTheme: (t: ThemePrefs) => void;
-  perf: boolean;
-  setPerf: (v: boolean) => void;
-  hints: boolean;
-  setHints: (v: boolean) => void;
-  railLabels: boolean;
-  setRailLabels: (v: boolean) => void;
-  notif: NotifSettings;
-  setNotif: (n: NotifSettings) => void;
-  saveState: PrefsSaveState;
-}
-
 type TabId = SettingsTabId;
 const TABS: { id: TabId; icon: typeof Monitor }[] = [
   { id: "appearance", icon: Monitor },
@@ -138,7 +119,7 @@ export default function SettingsPanel() {
 
 // A small transient indicator of the auto-save outcome. Renders nothing while idle; it sits at the
 // bottom of the settings card and fades after a success (the state resets to "idle" in App).
-function SaveIndicator({ state }: { state: PrefsSaveState }) {
+function SaveIndicator({ state }: { state: SaveState }) {
   const { t } = useTranslation();
   if (state === "idle") return null;
   return (

frontend/src/shell/App.tsx

@@ -21,8 +21,12 @@ import { LS } from "../lib/storage";
 import { usePref } from "../lib/usePref";
 import { useVerifyEntry } from "../lib/useVerifyEntry";
 import { useNavigation, useNavigationActions } from "../features/navigation/navigationContext";
-import { useFeedFilters, useFeedFiltersActions } from "../modules/feed/feedFiltersContext";
-import { useFeedView, useFeedViewActions } from "../modules/feed/feedViewContext";
+import {
+  useFeedFilters,
+  useFeedFiltersActions,
+  useFeedView,
+  useFeedViewActions,
+} from "../modules/feed";
 import { moduleOrder } from "../lib/modules";
 import { PAGE_CONTENT, PAGE_RAIL, preloadPages } from "./moduleRegistry";
 import { lazyWithPreload } from "../lib/lazyWithPreload";

frontend/src/shell/AppCommandPalette.dom.test.tsx

@@ -57,7 +57,7 @@ vi.mock("../modules/playlists/playlistsContext", () => ({
 vi.mock("../features/prefs/prefsContext", () => ({
   usePrefs: () => ({ theme: { scheme: "default" }, setTheme: vi.fn() }),
 }));
-vi.mock("../modules/feed/savedViewsContext", () => ({
+vi.mock("../features/filters/savedViewsContext", () => ({
   useSavedViews: () => ({ views: [], apply: vi.fn() }),
 }));
 const requestSurprise = vi.fn();

frontend/src/shell/AppCommandPalette.tsx

@@ -24,9 +24,9 @@ import { requestLinkBox } from "../lib/downloadIntake";
 import { openRecorderStart } from "../lib/debugRecorder";
 import { useDebugRecording } from "../features/diagnostics/useDebugRecording";
 import { useNavigationActions } from "../features/navigation/navigationContext";
-import { usePlaylistsActions } from "../modules/playlists/playlistsContext";
+import { usePlaylistsActions } from "../modules/playlists";
 import { usePrefs } from "../features/prefs/prefsContext";
-import { useSavedViews } from "../modules/feed/savedViewsContext";
+import { useSavedViews } from "../features/filters/savedViewsContext";
 
 // What Ctrl/Cmd+K can reach. The generic list/filter/keyboard shell is `ui/CommandPalette`; this is
 // the domain half — the layer boundary says a primitive may not import `lib/api` or a module.

frontend/src/shell/Header.palette.dom.test.tsx

@@ -11,24 +11,24 @@ vi.mock("react-i18next", async (importOriginal) => ({
 }));
 
 let page = "home";
-vi.mock("../navigation/navigationContext", () => ({ useNavigation: () => ({ page }) }));
-vi.mock("../../modules/feed/feedFiltersContext", () => ({
+vi.mock("../features/navigation/navigationContext", () => ({ useNavigation: () => ({ page }) }));
+vi.mock("../modules/feed/feedFiltersContext", () => ({
   useFeedFilters: () => ({ q: "", sort: "newest" }),
   useFeedFiltersActions: () => ({ setFilters: vi.fn() }),
 }));
-vi.mock("../../modules/playlists/playlistsContext", () => ({
+vi.mock("../modules/playlists/playlistsContext", () => ({
   usePlaylists: () => ({ search: "" }),
   usePlaylistsActions: () => ({ setSearch: vi.fn() }),
 }));
-vi.mock("../../modules/channels/channelsContext", () => ({
+vi.mock("../modules/channels/channelsContext", () => ({
   useChannels: () => ({ search: "" }),
   useChannelsActions: () => ({ setSearch: vi.fn(), goToFullHistory: vi.fn() }),
 }));
-vi.mock("../../modules/channels/SyncStatus", () => ({ default: () => null }));
+vi.mock("../modules/channels/SyncStatus", () => ({ default: () => null }));
 
-import Header from "../../shell/Header";
-import { closePalette, usePaletteOpen } from "../../lib/keymap";
-import type { Me } from "../../lib/api";
+import Header from "./Header";
+import { closePalette, usePaletteOpen } from "../lib/keymap";
+import type { Me } from "../lib/api";
 
 afterEach(() => {
   cleanup();

frontend/src/shell/Header.tsx

@@ -3,16 +3,21 @@ import { useTranslation } from "react-i18next";
 import { YouTubeIcon } from "../lib/brandIcons";
 import type { Me } from "../lib/api";
 import SearchBar from "../features/header/SearchBar";
-import { useFiles, useFilesActions } from "../modules/files/filesContext";
+import { useFiles, useFilesActions } from "../modules/files";
+// eslint-disable-next-line local/layers -- the header still hosts this module's control; it goes once each page renders its own controls into the header's slots.
 import PlexSearchBox from "../modules/plex/PlexSearchBox";
+// eslint-disable-next-line local/layers -- the header still hosts this module's control; it goes once each page renders its own controls into the header's slots.
 import PlexScopeToggle from "../modules/plex/PlexScopeToggle";
+// eslint-disable-next-line local/layers -- the header still hosts this module's control; it goes once each page renders its own controls into the header's slots.
 import PlexViewToggle from "../modules/plex/PlexViewToggle";
+// eslint-disable-next-line local/layers -- the header still hosts this module's control; it goes once each page renders its own controls into the header's slots.
 import FeedScopeToggle from "../modules/feed/FeedScopeToggle";
+// eslint-disable-next-line local/layers -- the header still hosts this module's control; it goes once each page renders its own controls into the header's slots.
 import SyncStatus from "../modules/channels/SyncStatus";
 import { useNavigation } from "../features/navigation/navigationContext";
-import { useFeedFilters, useFeedFiltersActions } from "../modules/feed/feedFiltersContext";
-import { usePlaylists, usePlaylistsActions } from "../modules/playlists/playlistsContext";
-import { useChannels, useChannelsActions } from "../modules/channels/channelsContext";
+import { useFeedFilters, useFeedFiltersActions } from "../modules/feed";
+import { usePlaylists, usePlaylistsActions } from "../modules/playlists";
+import { useChannels, useChannelsActions } from "../modules/channels";
 import { PaletteLauncher } from "../features/header/PaletteLauncher";
 
 // The floating top header: a row of glass pills over the content — the module's SearchBar where it

frontend/src/shell/moduleRegistry.tsx

@@ -2,8 +2,11 @@ import type { ComponentType } from "react";
 import { lazyWithPreload, type PreloadableComponent } from "../lib/lazyWithPreload";
 import type { Page } from "../lib/urlState";
 import type { PanelId, PanelLayout } from "../lib/panelLayout";
+// eslint-disable-next-line local/layers -- a rail (or the feed page's wrapper) the shell still loads eagerly; it goes once every rail loads lazily, like the pages.
 import Sidebar from "../modules/feed/Sidebar";
+// eslint-disable-next-line local/layers -- a rail (or the feed page's wrapper) the shell still loads eagerly; it goes once every rail loads lazily, like the pages.
 import PlaylistsRail from "../modules/playlists/PlaylistsRail";
+// eslint-disable-next-line local/layers -- a rail (or the feed page's wrapper) the shell still loads eagerly; it goes once every rail loads lazily, like the pages.
 import { Feed, FeedPage } from "../modules/feed/modulePages";
 
 // The RENDER half of the module registry: which component (and side rail) each page renders. The

frontend/tsconfig.node.json

@@ -43,6 +43,8 @@
     "vitest.config.ts",
     "reactPlugin.ts",
     "devOnlyGuard.ts",
+    "chunkGuard.ts",
+    "src/lib/chunkLeaks.ts",
     "playwright.config.ts",
     "postcss.config.js"
   ]

frontend/vite.config.ts

@@ -2,6 +2,7 @@ import { ServerResponse } from "node:http";
 import { defineConfig, type Plugin, type ProxyOptions } from "vite";
 import { reactWithCompiler } from "./reactPlugin";
 import { devOnlyGuard } from "./devOnlyGuard";
+import { chunkGuard } from "./chunkGuard";
 
 // During `vite dev` (host with Node), proxy API calls to the backend container.
 // Use 127.0.0.1 (not "localhost") so Node doesn't resolve to IPv6 ::1, which the
@@ -54,7 +55,7 @@ const watchEntry = (): Plugin => ({
 });
 
 export default defineConfig({
-  plugins: [reactWithCompiler(), devOnlyGuard(), watchEntry()],
+  plugins: [reactWithCompiler(), devOnlyGuard(), chunkGuard(), watchEntry()],
   server: { port: 5173, proxy },
   build: { outDir: "dist", rollupOptions: { input: ["index.html", "watch.html"] } },
 });