fix(frontend): the chunk guard's logic lives in the guard, so no file sits in two TypeScript projects

The guard's logic was a src/lib file the config project also listed. The app project, which
references the config project, then refuses that source on a clean build (TS6305) — while every
local run reused the referenced project's cached output and stayed green; only the Docker image
build failed. The logic is back inside chunkGuard.ts, its test beside it at the frontend root
(vitest now also collects `*.test.ts` there), and a gate contract fails when the config project's
include reaches into src/ again. The guard was re-proved on a build with a leaking re-export.

frontend/chunkGuard.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { bootLeaks, type ChunkLike } from "./chunkLeaks";
+import { bootLeaks, type ChunkLike } from "./chunkGuard";
 
 const APP = "/r/src/shell/App.tsx";
 const chunk = (fileName: string, moduleIds: string[], imports: string[] = [], isEntry = false) =>

frontend/chunkGuard.ts

@@ -1,12 +1,45 @@
 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.
+// A lazily imported page, rail, dialog or player must stay out of the chunks loaded at boot. A page
+// is imported with import()/lazy() so it is fetched only when it is opened, and Rollup honours that
+// only while nothing on the boot path imports the same module statically: one static import — a
+// module's index.ts re-exporting it is the easy way — and the module joins a boot chunk, the import()
+// becomes a no-op, and nothing says so. That rule used to be a hope; this makes it a build failure,
+// naming each module and the boot chunk it landed in. 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.
 const SHELL = "src/shell/App.tsx";
 
+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) 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(`/${shell}`);
+  const boot = new Set<ChunkLike>();
+  const visit = (c: ChunkLike | undefined) => {
+    if (!c || boot.has(c)) return;
+    boot.add(c);
+    c.imports.forEach((name) => visit(byName.get(name)));
+  };
+  chunks.filter((c) => c.isEntry || c.moduleIds.some(isShell)).forEach(visit);
+  const leaks: string[] = [];
+  for (const c of boot)
+    for (const id of c.moduleIds)
+      if (lazy.has(id) && !isShell(id)) leaks.push(`${posix(id)} (${c.fileName})`);
+  return leaks.sort();
+}
+
 export function chunkGuard(): Plugin {
   return {
     name: "siftlode-chunk-guard",

frontend/eslint.config.js

@@ -845,7 +845,14 @@ 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", "chunkGuard.ts"],
+    files: [
+      "e2e/**/*.ts",
+      "*.config.ts",
+      "reactPlugin.ts",
+      "devOnlyGuard.ts",
+      "chunkGuard.ts",
+      "chunkGuard.test.ts",
+    ],
     extends: [js.configs.recommended, ...tseslint.configs.recommended],
     languageOptions: {
       ecmaVersion: 2022,

frontend/src/lib/chunkLeaks.ts

@@ -1,40 +0,0 @@
-// 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

@@ -472,7 +472,7 @@ describe("the gate register (docs/gates.md)", () => {
       "reactPlugin.ts",
       "devOnlyGuard.ts",
       "chunkGuard.ts",
-      "src/lib/chunkLeaks.ts",
+      "chunkGuard.test.ts",
       "playwright.config.ts",
       "postcss.config.js",
     ],
@@ -490,6 +490,14 @@ describe("the gate register (docs/gates.md)", () => {
     }
     expect(missingFrom(found)).toEqual([]);
   });
+  it("puts no file in two projects", () => {
+    // A src file the config project also lists builds into that project's output, and the app
+    // project (which references it) then refuses the source (TS6305) — but only on a clean
+    // build: a local run reuses the referenced project's cached output and stays green, so only
+    // the Docker image build said so.
+    const node = jsonc("frontend/tsconfig.node.json").include as string[];
+    expect(node.filter((f) => f === "src" || f.startsWith("src/"))).toEqual([]);
+  });
   it("type-checks every config file at the frontend root, or lists it", () => {
     const checked = new Set(INCLUDE["frontend/tsconfig.node.json"]);
     const roots = readdirSync(FRONTEND).filter((f) => /[.](ts|js|mjs|cjs)$/.test(f));

frontend/src/lib/gates.snapshot.json

@@ -1287,7 +1287,7 @@
       "export default defineConfig({",
       "  plugins: [reactWithCompiler()],",
       "  test: {",
-      "    include: [\"src/**/*.test.{ts,tsx}\"],",
+      "    include: [\"src/**/*.test.{ts,tsx}\", \"*.test.ts\"],",
       "    environment: \"node\",",
       "    coverage: {",
       "      provider: \"v8\",",

frontend/tsconfig.node.json

@@ -44,7 +44,7 @@
     "reactPlugin.ts",
     "devOnlyGuard.ts",
     "chunkGuard.ts",
-    "src/lib/chunkLeaks.ts",
+    "chunkGuard.test.ts",
     "playwright.config.ts",
     "postcss.config.js"
   ]

frontend/vitest.config.ts

@@ -17,7 +17,8 @@ export default defineConfig({
   test: {
     // .tsx included on purpose: a test file the glob misses does not fail, it is simply never
     // collected, and the gate still prints green.
-    include: ["src/**/*.test.{ts,tsx}"],
+    // …and the build plugins' own tests beside them at the frontend root (chunkGuard).
+    include: ["src/**/*.test.{ts,tsx}", "*.test.ts"],
     environment: "node",
     // A coverage REPORT on demand (`npm run test -- --coverage`), never enforced and not in the gate:
     // "every regression test seen red" is the bar, not a percentage.