fix(user-flow): close offline-queue, export, session, ban & realtime gaps

Comprehensive user-flow review across guest/host/admin roles, then fixes with
e2e regression guards. Highlights:

- Offline upload queue auto-resumes on reconnect: network errors keep items
  pending (not error), 4xx are terminal (no infinite retry), quota exhaustion
  returns a distinct 413; queue cap + dedup.
- Export lifecycle: release atomically locks uploads; reopen invalidates and
  re-release regenerates the keepsake; workers claim their job atomically so a
  reopen->re-release can't corrupt the ZIP; startup re-spawns interrupted
  exports.
- Sessions slide on activity (no 30-day cliff); JWT expiry deferred to the
  revocable session row; sign-out-everywhere + revoke-on-PIN-reset.
- Ban always hides content (v_feed / find_visible_media / export filter
  is_banned) but stays a read-only ban per USER_JOURNEYS §10 — sessions are
  not revoked, read access + keepsake download preserved.
- Realtime: server-clock SSE delta cursor; event-closed/opened drive the UI
  live; feed_delta rate-limited; like returns {liked, like_count} to fix
  multi-device drift; lightbox live comments; diashow delta backfill.
- Forgotten-PIN in-app request flow; simultaneous same-name join returns 409;
  quota increment is transactional; operator floor.

Adds e2e/specs/10-flow-review/ (offline resume, export integrity, deterministic
anti-race guard) and updates existing specs for the new contracts.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/lib/components/UploadQueue.svelte

@@ -14,6 +14,7 @@
 			case 'uploading': return 'Wird hochgeladen';
 			case 'done': return 'Fertig';
 			case 'error': return 'Fehler';
+			case 'blocked': return 'Gesperrt';
 		}
 	}
 
@@ -23,6 +24,7 @@
 			case 'uploading': return 'text-blue-600 dark:text-blue-400';
 			case 'done': return 'text-green-600 dark:text-green-400';
 			case 'error': return 'text-red-600 dark:text-red-400';
+			case 'blocked': return 'text-red-600 dark:text-red-400';
 		}
 	}
 
@@ -94,7 +96,7 @@
 									Erneut
 								</button>
 							{/if}
-							{#if item.status === 'done' || item.status === 'error'}
+							{#if item.status === 'done' || item.status === 'error' || item.status === 'blocked'}
 								<button
 									onclick={() => removeItem(item.id)}
 									class="inline-flex h-9 w-9 items-center justify-center text-gray-400 hover:text-gray-600 dark:text-gray-500 dark:hover:text-gray-300"