feat(web): unified reader with reading settings, faster lists, a11y

- New Reader (desktop + mobile): loads full content on open, prefetches
  the next article, reading progress and time, "Aa" settings (light /
  sepia / dark / auto theme, serif / sans / Atkinson Hyperlegible font,
  size, line height, measure), Space-to-next, keyboard shortcuts, focus
  management, inert background, URL-driven (?a=) so Back closes it.
- Dashboard: cursor pagination, unread/all filter, CSS grid (no masonry),
  no re-sorting under the reader, optimistic cache patches instead of
  refetch storms, "new articles" banner, error/offline states, j/k/o/m/s/v
  shortcuts and help dialog.
- Cards: keyboard-openable, lazy <img>, memoized, touch-only swipe.
- Focus mode: framer drag (drop @use-gesture), Read button, undo restores
  unread state, arrow keys.
- WebSocket: single connection, backoff, cache patching, no console logs.
- Contrast fixes (on-nature tokens), 44px targets, lang="fr", reduced
  motion, self-hosted fonts, theme applied before first paint.
- Code splitting + vendor chunk, prompt-based PWA updates, smaller
  precache, offline cache for opened articles and images, caches cleared
  on logout; upgrade react-router (CVE), drop unused deps and assets.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/stores/authStore.ts

@@ -10,6 +10,7 @@ interface User {
 interface AuthState {
     user: User | null;
     isAuthenticated: boolean;
+    /** True until the first /users/me answer when nothing is persisted. */
     isLoading: boolean;
     setUser: (user: User | null) => void;
     setLoading: (loading: boolean) => void;
@@ -24,7 +25,7 @@ export const useAuthStore = create<AuthState>()(
             isLoading: true,
             setUser: (user) => set({ user, isAuthenticated: !!user, isLoading: false }),
             setLoading: (isLoading) => set({ isLoading }),
-            logout: () => set({ user: null, isAuthenticated: false }),
+            logout: () => set({ user: null, isAuthenticated: false, isLoading: false }),
         }),
         {
             name: 'auth-storage',
@@ -32,3 +33,15 @@ export const useAuthStore = create<AuthState>()(
         }
     )
 );
+
+/** Clears every client-side copy of the user's data (logout / expired session). */
+export async function clearUserData() {
+    try {
+        if ('caches' in window) {
+            const keys = await caches.keys();
+            await Promise.all(keys.filter((k) => k.startsWith('api') || k === 'images').map((k) => caches.delete(k)));
+        }
+    } catch {
+        /* ignore */
+    }
+}