fix(user-flow): persona-audit fixes — ban replay, locked-upload data loss, host UX, admin session

Follows the perf + security + user-flow work with a role/persona audit (guest, host,
admin, projector) and fixes across three review rounds. Highlights:

HIGH
- Ban now replays on reconnect. A ban isn't a soft-delete, and the `user-hidden` SSE has
  no replay, so a client that missed it (esp. the unattended diashow) kept cycling a
  banned user's slides. New `uploads_hidden_at` (migration 013) + `hidden_user_ids` in
  /feed/delta; feed + diashow evict those users. Applied even on a truncated delta.

MEDIUM
- Locked-upload data loss: a photo staged offline during a lock/release was purged as a
  terminal 4xx and lost when the host reopened. New reversible `uploads_locked` error code;
  the queue keeps the blob and auto-resumes on the `event-opened` SSE.
- Reopen after release now warns (ConfirmSheet) that it revokes the published keepsake.
- Host "forgotten-PIN" badge updates live (`pin-reset-requested` was broadcast but never
  in KNOWN_EVENTS / subscribed); host page also refetches on `pin-reset` so a two-host
  race can't hand out a conflicting PIN.
- Ban modal copy fixed (read-only ban, not "session ended"); Degradieren/Sperren/Entsperren
  hidden on peer-host rows for non-admins (they always 403'd).
- Host dashboard shows live keepsake generation progress / ready state + link to /export.
- Admin JWT moved to sessionStorage (§11.1) to bound exposure on shared devices.

Export generation guard (H1 from the prior round, hardened): per-(event,type) `release_seq`
(migration 012) with seq-guarded claim/finalize/mark_failed/update_progress, per-generation
temp/final paths, download follows `file_path`, prune only strictly-older generations.

LOW: diashow coalesces upload-processed (avoids self-rate-limit); event-closed reconciles
galleryReleased; /recover gains a forgot-PIN request + drops a stale cached PIN on 401;
delta `>=` tie-break + 429 retry; misc copy/labels.

Adds e2e: ban-replay, upload-lock-code, and rewrites export-reopen-rerelease with a
data-completeness test. Reconciles USER_JOURNEYS §9/§11.

Verified: cargo build clean, 40 unit tests, svelte-check 0 errors, 33 frontend unit
tests, 155 e2e passing on chromium-desktop.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

e2e/specs/01-auth/admin-login.spec.ts

@@ -13,17 +13,24 @@ test.describe('Auth — admin login', () => {
     await login.login(ADMIN_PASSWORD);
     await page.waitForURL('**/admin', { timeout: 10_000 });
 
-    // Admin JWT should now be in localStorage (admin uses the same key, just with role=admin in the payload)
-    const role = await page.evaluate(() => {
-      const token = localStorage.getItem('eventsnap_jwt');
-      if (!token) return null;
-      try {
-        return JSON.parse(atob(token.split('.')[1])).role;
-      } catch {
-        return null;
-      }
+    // The admin JWT lands in sessionStorage (USER_JOURNEYS §11.1) — NOT localStorage — so the
+    // elevated credential doesn't survive a tab/browser close on a shared "event laptop".
+    const stores = await page.evaluate(() => {
+      const decodeRole = (t: string | null) => {
+        if (!t) return null;
+        try {
+          return JSON.parse(atob(t.split('.')[1])).role;
+        } catch {
+          return null;
+        }
+      };
+      return {
+        sessionRole: decodeRole(sessionStorage.getItem('eventsnap_jwt')),
+        localToken: localStorage.getItem('eventsnap_jwt')
+      };
     });
-    expect(role).toBe('admin');
+    expect(stores.sessionRole).toBe('admin');
+    expect(stores.localToken, 'admin token must not persist in localStorage').toBeNull();
   });
 
   test('wrong password → error, no token written', async ({ page }) => {