fix(review-2): high — read-only ban model, failed-compression cleanup, live SSE eviction

H1: corrected a round-1 over-reach. Bans are read-only per USER_JOURNEYS §10:
    the base AuthUser extractor no longer rejects banned users (they keep read
    access); Require{Host,Admin} and write handlers enforce the ban via
    auth.is_banned → 403 (incl. self-unban). Demoted hosts still lose powers
    immediately (live DB role) and are bounced off the dashboard. Also fixed the
    login/recover redirect regression on unauthenticated 401.

H2: failed compression now self-heals instead of leaving a permanent broken
    card — refund the quota, delete the orphaned original, soft-delete the row;
    the frontend toasts the uploader and evicts the card on upload-error.

H3: self-delete, ban-with-hide (user-hidden), and comment-deletes now broadcast
    SSE; feed, diashow, and lightbox evict the affected content live instead of
    waiting for a reload. sse-eviction.spec.ts covers it.

Riders: feed/+page.svelte also carries the medium truncated-delta pill; host.rs
also carries the low atomic release_gallery claim; admin/+page.svelte also drops
the dead compression_concurrency control (medium).

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

frontend/src/lib/api.ts

@@ -68,6 +68,9 @@ async function request<T>(
 	}
 
 	if (!res.ok) {
+		// An expired/invalid token (401) clears the dead session. Banned users are
+		// NOT logged out — they keep read access by design (USER_JOURNEYS §10) and
+		// simply get a 403 "gesperrt" toast on writes.
 		if (res.status === 401) {
 			clearAuth();
 		}

frontend/src/lib/diashow/queue.ts

@@ -73,6 +73,23 @@ export class SlideQueue {
 		return { wasCurrent: currentId === id };
 	}
 
+	/**
+	 * Remove every slide belonging to a user (banned with hide_uploads). Returns
+	 * true if the current head was one of them so the caller advances immediately.
+	 */
+	removeByUser(userId: string, currentId: string | null): { wasCurrent: boolean } {
+		let wasCurrent = false;
+		for (const [id, slide] of this.allKnown) {
+			if (slide.user_id === userId) {
+				if (id === currentId) wasCurrent = true;
+				this.allKnown.delete(id);
+			}
+		}
+		this.liveQueue = this.liveQueue.filter((s) => s.user_id !== userId);
+		this.shuffleQueue = this.shuffleQueue.filter((s) => s.user_id !== userId);
+		return { wasCurrent };
+	}
+
 	/** Look up a slide by id — for the diashow page to render the current slide. */
 	get(id: string): FeedUpload | undefined {
 		return this.allKnown.get(id);