fix(events): production wiring + polling resilience (quick wins)

Five small follow-ups on Phase 1b:

- docker-compose.macmini.yml: add the mana-events container with the
  same shape as mana-credits, expose port 3065, add a Traefik route
  for events.mana.how, and inject PUBLIC_MANA_EVENTS_URL into the
  mana-web container so the SvelteKit SSR + browser both reach it.
- mana-events: background sweeper that deletes rsvp_rate_buckets
  rows older than 2h every hour. Without it, long-published events
  accumulate one row per traffic-hour forever (FK cascade only fires
  on snapshot delete).
- PublicRsvpList: track consecutiveFailures and only show the error
  banner after two failures in a row, so a single mid-poll network
  hiccup doesn't flash a 30s error the user can't act on.
- apps/mana/apps/web: declare postgres as a devDep (already imported
  by the e2e spec via pnpm hoisting, now explicit).

apps/mana/apps/web/package.json

@@ -31,6 +31,7 @@
 		"autoprefixer": "^10.4.20",
 		"fake-indexeddb": "^6.2.5",
 		"postcss": "^8.4.49",
+		"postgres": "^3.4.9",
 		"prettier": "^3.4.2",
 		"prettier-plugin-svelte": "^3.3.2",
 		"prettier-plugin-tailwindcss": "^0.6.10",

apps/mana/apps/web/src/lib/modules/events/components/PublicRsvpList.svelte

@@ -11,19 +11,26 @@
 
 	let rsvps = $state<PublicRsvpRecord[]>([]);
 	let loading = $state(false);
-	let lastError = $state<string | null>(null);
+	let lastErrorMessage = $state<string | null>(null);
+	let consecutiveFailures = $state(0);
 	let lastFetchedAt = $state<Date | null>(null);
 
+	// Surface the error only after two failures in a row so a single network
+	// hiccup mid-poll doesn't flash a scary banner the user can't act on.
+	const showError = $derived(consecutiveFailures >= 2 && lastErrorMessage !== null);
+
 	async function fetchRsvps() {
 		if (!isPublished) return;
 		loading = true;
 		try {
 			const res = await eventsApi.getRsvps(eventId);
 			rsvps = res.rsvps;
-			lastError = null;
+			lastErrorMessage = null;
+			consecutiveFailures = 0;
 			lastFetchedAt = new Date();
 		} catch (e) {
-			lastError = e instanceof Error ? e.message : 'Fehler beim Laden';
+			lastErrorMessage = e instanceof Error ? e.message : 'Fehler beim Laden';
+			consecutiveFailures++;
 		} finally {
 			loading = false;
 		}
@@ -62,8 +69,8 @@
 			</button>
 		</div>
 
-		{#if lastError}
-			<p class="error">{lastError}</p>
+		{#if showError}
+			<p class="error">{lastErrorMessage}</p>
 		{:else if rsvps.length === 0 && !loading}
 			<p class="empty">Noch keine Antworten via Share-Link.</p>
 		{:else}