feat: storage management (retention, source purge) + Synology NAS backup

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XNQ8ghPfzAfsyVYd6HgFb6

src/pages/api/admin/storage.ts

@@ -0,0 +1,21 @@
+import type { APIRoute } from 'astro';
+import { storageStats, runRetention, purgeSources } from '../../../lib/maintenance';
+import { one } from '../../../lib/db';
+
+export const prerender = false;
+const json = (b: unknown, s = 200) =>
+  new Response(JSON.stringify(b), { status: s, headers: { 'Content-Type': 'application/json' } });
+
+export const GET: APIRoute = async () => json({ stats: await storageStats() });
+
+// POST { action: 'retention' | 'purge_sources' }
+export const POST: APIRoute = async ({ request }) => {
+  const b = await request.json().catch(() => ({}));
+  if (b.action === 'purge_sources') return json(await purgeSources());
+  if (b.action === 'retention') {
+    const s = await one<{ retention_days: number | null }>('SELECT retention_days FROM settings WHERE id=1');
+    if (!s?.retention_days) return json({ error: 'Keine Aufbewahrungsfrist gesetzt.' }, 400);
+    return json(await runRetention(s.retention_days));
+  }
+  return json({ error: 'Unbekannte Aktion.' }, 400);
+};