refactor(channels): adopt shared Tabs + usePersistedTab for the manager tab row (R13 S2b)

Retire the hand-rolled channel-manager view pills for the shared <Tabs> component (given an
optional className so it embeds in the justify-between header without the default mb-4), and
back view + layout on usePersistedTab instead of manual getAccountRaw/setAccountRaw useState.
That subsumes the account-pin re-hydrate (usePersistedTab now re-reads on the pin), so
ChannelsProvider's bespoke markManagerDirty/useAccountRehydrate is gone; setView keeps the
history-tab logic (_chTab pushState + popstate) layered on the stable raw setter, and
useAccountPersistedState's setter is now memoized so that stable action holds.

Per the user's call, unify every channel-manager pill on the rounded-lg idiom: the view tabs
via <Tabs>, the sync chips and tag chips + the "manage tags" affordance from rounded-full to
rounded-lg — no more odd-one-out rounded-full.

gate-green: tsc + vitest 120 + eslint-0 + knip + prettier. Self-E2E'd: tab switch, browser
Back across tabs (Blocked->Hidden->Subscriptions with localStorage in sync), and a fresh tab
restoring view=hidden on the FIRST load; zero console errors.

frontend/src/components/Channels.tsx

@@ -12,6 +12,7 @@ import { buildChannelColumns } from "./channelColumns";
 import { notify } from "../lib/notifications";
 import Tooltip from "./Tooltip";
 import DataTable from "./DataTable";
+import Tabs, { type TabDef } from "./Tabs";
 import ChannelLayoutGrid from "./ChannelLayoutGrid";
 import { LoadingState, StateMessage } from "./QueryState";
 import { useChannelTagActions } from "../lib/useChannelTagActions";
@@ -299,7 +300,7 @@ export default function Channels() {
           key={c.value || "all"}
           onClick={() => setFilters({ ...filters, sync: c.value })}
           aria-pressed={syncFilter === c.value}
-          className="pill text-xs px-2.5 py-1 rounded-full border"
+          className="pill text-xs px-2.5 py-1 rounded-lg border"
         >
           {t(c.labelKey)}
         </button>
@@ -431,20 +432,17 @@ export default function Channels() {
   }, [filters, search, sort, resetPage]);
   const cardPager = <Pager {...pagerProps} />;
 
+  const viewTabs: TabDef[] = (
+    ["subscribed", "discovery", "hidden", "blocked"] as ChannelsView[]
+  ).map((v) => ({ id: v, label: t(`channels.tabs.${v}`) }));
   const tabs = (
     <div className="px-4 pt-4 max-w-384 mx-auto flex items-center justify-between gap-4 flex-wrap">
-      <div className="flex flex-wrap items-center gap-1.5">
+      <Tabs
-        {(["subscribed", "discovery", "hidden", "blocked"] as ChannelsView[]).map((v) => (
+        tabs={viewTabs}
-          <button
+        active={view}
-            key={v}
+        onChange={(id) => setView(id as ChannelsView)}
-            onClick={() => setView(v)}
+        className="flex flex-wrap items-center gap-1"
-            aria-pressed={view === v}
+      />
-            className="pill text-sm px-3 py-1.5 rounded-full border"
-          >
-            {t(`channels.tabs.${v}`)}
-          </button>
-        ))}
-      </div>
       <div className="flex items-center gap-3">
         {view === "subscribed" && statsBlock}
         {view === "subscribed" && layout === "cards" && sortControl}
@@ -476,7 +474,7 @@ export default function Channels() {
                     key={tg.id}
                     onClick={() => toggleTagFilter(tg.id)}
                     aria-pressed={tagFilter.includes(String(tg.id))}
-                    className="pill text-xs px-2 py-1 rounded-full border"
+                    className="pill text-xs px-2 py-1 rounded-lg border"
                   >
                     {tg.name}
                   </button>
@@ -491,7 +489,7 @@ export default function Channels() {
                 )}
                 <button
                   onClick={() => setTagManagerOpen(true)}
-                  className="inline-flex items-center gap-1 text-xs px-2 py-1 rounded-full border border-dashed border-border text-muted hover:text-accent hover:border-accent transition"
+                  className="inline-flex items-center gap-1 text-xs px-2 py-1 rounded-lg border border-dashed border-border text-muted hover:text-accent hover:border-accent transition"
                 >
                   <Pencil className="w-3 h-3" />
                   {t("channels.tags.manage")}

frontend/src/components/ChannelsProvider.tsx

@@ -8,12 +8,12 @@ import {
   useState,
   type ReactNode,
 } from "react";
-import { getAccountRaw, LS, setAccountRaw } from "../lib/storage";
+import { getAccountRaw, LS } from "../lib/storage";
 import { parseChannelLayout, type ChannelLayout } from "../lib/channelLayout";
 import { type SortState } from "../lib/columnSort";
 import { useSortState } from "../lib/useSortState";
 import { useFilterState } from "../lib/useFilterState";
-import { useAccountRehydrate } from "../lib/useAccountRehydrate";
+import { usePersistedTab } from "./Tabs";
 import type { FilterMap } from "./tableHeader";
 import { useNavigation, useNavigationActions } from "./NavigationProvider";
 import type { ChannelsView } from "./Channels";
@@ -117,12 +117,14 @@ export function ChannelsProvider({ children }: { children: ReactNode }) {
   // The subscribed table's column-filter map, owned here (lifted out of DataTable) so the top status
   // chips, the Sync column funnel, and the card layout share one state; useFilterState persists it.
   const [filters, setFilters] = useFilterState(LS.channelsFilterMap, migrateSyncChip);
-  const [view, setViewState] = useState<ChannelsView>(() =>
+  // view + layout are persisted tabs (usePersistedTab = the shared account-scoped tab-state hook), so
-    clampView(getAccountRaw(LS.channelsView)),
+  // they get init-from-storage AND the account-pin re-hydrate for free (this provider mounts above
-  );
+  // <App>, which pins the account only after /api/me). Stored un-clamped; clampView/parseChannelLayout
-  const [layout, setLayoutState] = useState<ChannelLayout>(() =>
+  // heal them for display. setView layers the history logic (below) on top of the raw setter.
-    parseChannelLayout(getAccountRaw(LS.channelLayout)),
+  const [viewRaw, setViewRaw] = usePersistedTab(LS.channelsView, "subscribed");
-  );
+  const view = clampView(viewRaw);
+  const [layoutRaw, setLayout] = usePersistedTab(LS.channelLayout, "table");
+  const layout = parseChannelLayout(layoutRaw);
   // Sort is owned here (lifted out of DataTable) so the card layout shares it; ColumnSortControl heals
   // it against the live columns for display, so the provider stores it un-healed (no options passed).
   const [sort, setSort] = useSortState(LS.channelSort);
@@ -130,15 +132,6 @@ export function ChannelsProvider({ children }: { children: ReactNode }) {
   const [focusName, setFocusName] = useState<string | null>(null);
   const [focusToken, setFocusToken] = useState(0);
 
-  // view + layout (like sort/filters) initialise from an unknown account on first load, because this
-  // provider mounts above <App>, which pins the account only after /api/me resolves. Re-read them once
-  // the account is known. Uses the raw state setters (not setView/setLayout) so it's a silent
-  // correction, not a history-pushing navigation; markManagerDirty guards a user switch made pre-pin.
-  const markManagerDirty = useAccountRehydrate(() => {
-    setViewState(clampView(getAccountRaw(LS.channelsView)));
-    setLayoutState(parseChannelLayout(getAccountRaw(LS.channelLayout)));
-  });
-
   // Latest-value ref so the STABLE setView can compare against the current tab without depending on
   // it (a dep would recreate the action on every switch and re-render every actions consumer).
   // Written during render — the sanctioned pattern NavigationProvider uses for `pageRef`.
@@ -154,9 +147,7 @@ export function ChannelsProvider({ children }: { children: ReactNode }) {
       // Re-selecting the tab you are already on is not a navigation — bail before pushing, or clicking
       // the active tab (and goToFullHistory forcing "subscribed") stacks Back entries that do nothing.
       if (v === viewRef.current) return;
-      markManagerDirty();
+      setViewRaw(v); // persists + guards the account-pin re-hydrate (via usePersistedTab)
-      setViewState(v);
-      setAccountRaw(LS.channelsView, v);
       // Only own an entry while the manager is already on screen. Arriving from elsewhere
       // (focusChannel / goToFullHistory) lets setPage push the entry — the stamp effect labels it — so
       // one navigation never costs two Back presses.
@@ -166,15 +157,7 @@ export function ChannelsProvider({ children }: { children: ReactNode }) {
         window.history.pushState({ sfPage: "channels", _chTab: v }, "");
       }
     },
-    [markManagerDirty],
+    [setViewRaw],
-  );
-  const setLayout = useCallback(
-    (l: ChannelLayout) => {
-      markManagerDirty();
-      setLayoutState(l);
-      setAccountRaw(LS.channelLayout, l);
-    },
-    [markManagerDirty],
   );
   const focusChannel = useCallback(
     (name: string) => {
@@ -212,13 +195,11 @@ export function ChannelsProvider({ children }: { children: ReactNode }) {
     function onPop(e: PopStateEvent) {
       const tab = e.state?._chTab;
       if (!tab) return; // an entry outside the manager — leave the tab alone
-      const next = clampView(tab as string);
+      setViewRaw(clampView(tab as string)); // persists the restored tab (setViewRaw is stable)
-      setViewState(next);
-      setAccountRaw(LS.channelsView, next);
     }
     window.addEventListener("popstate", onPop);
     return () => window.removeEventListener("popstate", onPop);
-  }, []);
+  }, [setViewRaw]);
 
   const state = useMemo<ChannelsState>(
     () => ({ search, filters, view, sort, filtersResetToken, focusName, focusToken }),

frontend/src/components/Tabs.tsx

@@ -18,13 +18,17 @@ export default function Tabs({
   tabs,
   active,
   onChange,
+  className = "flex flex-wrap gap-1 mb-4",
 }: {
   tabs: TabDef[];
   active: string;
   onChange: (id: string) => void;
+  // Override the row wrapper — e.g. the channel manager embeds the rail in a justify-between header
+  // and drops the default bottom margin. Omit for the standalone-row default.
+  className?: string;
 }) {
   return (
-    <div className="flex flex-wrap gap-1 mb-4">
+    <div className={className}>
       {tabs.map((tb) => {
         const on = tb.id === active;
         return (

frontend/src/lib/storage.ts

@@ -159,11 +159,16 @@ export function useAccountPersistedState(
 ): [string, (value: string) => void] {
   const [value, setValue] = useState<string>(() => getAccountRaw(base) ?? fallback);
   const markDirty = useAccountRehydrate(() => setValue(getAccountRaw(base) ?? fallback));
-  const set = (next: string) => {
+  // Stable setter (base + markDirty are both stable) so a provider can build a stable action on top
+  // of it — e.g. ChannelsProvider's setView, which must not change identity on every tab switch.
+  const set = useCallback(
+    (next: string) => {
       markDirty();
       setValue(next);
       setAccountRaw(base, next);
-  };
+    },
+    [base, markDirty],
+  );
   return [value, set];
 }