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>

frontend/src/routes/upload/+page.svelte

@@ -2,6 +2,7 @@
 	import { goto } from '$app/navigation';
 	import { getToken } from '$lib/auth';
 	import { addToQueue, loadQueue } from '$lib/upload-queue';
+	import { toast } from '$lib/toast-store';
 	import { showBottomNav } from '$lib/ui-store';
 	import { pendingFiles, pendingCaption, clearPending } from '$lib/pending-upload-store';
 	import { get } from 'svelte/store';
@@ -98,8 +99,18 @@
 		submitting = true;
 		vibrate(10);
 		const hashtagsString = captionTags.join(',');
+		let full = 0;
 		for (const sf of stagedFiles) {
-			await addToQueue(sf.file, caption, hashtagsString);
+			const result = await addToQueue(sf.file, caption, hashtagsString);
+			if (result === 'full') full++;
+		}
+		// Don't let a full queue silently swallow photos the user thinks were queued.
+		if (full > 0) {
+			toast(
+				`Warteschlange voll – ${full} ${full === 1 ? 'Foto' : 'Fotos'} nicht hinzugefügt. Bitte warte, bis laufende Uploads fertig sind.`,
+				'error',
+				6000
+			);
 		}
 		clearPending();
 		goto('/feed');