Wochen-Rückblick: sonntags 20:00 automatisch in den Devlog-Kanal

- Scheduler (5-Minuten-Check, dedupe über last_weekly_recap-Setting)
- Embed: Commits pro Tag als Balken-Grafik, Commit-/Devlog-Zahlen, Top-Projekte
- Setting weekly_recap_enabled + 'Rückblick jetzt testen'-Button auf der Setup-Seite
- TZ Europe/Berlin im Compose (Scheduler + Datumsformate)

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

src/db.js

@@ -211,6 +211,28 @@ export function listReleases(limit, offset) {
     return { items: selectReleases.all(limit, offset), total: countReleasesStmt.get().n };
 }
 
+/** Zahlen der letzten 7 Tage für den Wochen-Rückblick */
+export function weeklyStats() {
+    const perDay = db
+        .prepare(`
+            SELECT date(committed_at) AS day, count(*) AS n
+            FROM commits WHERE committed_at >= datetime('now', '-7 days')
+            GROUP BY day
+        `)
+        .all();
+    const topRepos = db
+        .prepare(`
+            SELECT repo, count(*) AS n
+            FROM commits WHERE committed_at >= datetime('now', '-7 days')
+            GROUP BY repo ORDER BY n DESC LIMIT 3
+        `)
+        .all();
+    const devlogs = db
+        .prepare(`SELECT count(*) AS n FROM devlogs WHERE posted_at >= datetime('now', '-7 days')`)
+        .get().n;
+    return { perDay, topRepos, devlogs };
+}
+
 /** Statistiken fürs Status-Panel der Settings-Seite */
 export function archiveStats() {
     return {