feat: auto-cleanup logs older than 7 days

Request logs and reaction logs are automatically pruned on each request
via waitUntil. Zero-cost async cleanup, no cron needed.

小橘 🍊（NEKO Team）

packages/engine/src/index.ts

@@ -79,7 +79,10 @@ app.use('*', async (c, next) => {
   if (path === '/health' || path.startsWith('/ui')) return
 
   try {
+    const SEVEN_DAYS_MS = 7 * 24 * 60 * 60 * 1000
+    const cutoff = Date.now() - SEVEN_DAYS_MS
     c.executionCtx.waitUntil(
+      Promise.all([
         c.env.DB.prepare(
           'INSERT INTO request_logs (method, path, api_key_id, api_key_name, status_code, error, duration_ms, created_at) VALUES (?, ?, ?, ?, ?, ?, ?, ?)',
         )
@@ -99,6 +102,10 @@ app.use('*', async (c, next) => {
             Date.now(),
           )
           .run(),
+        // Cleanup logs older than 7 days
+        c.env.DB.prepare('DELETE FROM request_logs WHERE created_at < ?').bind(cutoff).run(),
+        c.env.DB.prepare('DELETE FROM reaction_logs WHERE created_at < ?').bind(cutoff).run(),
+      ]),
     )
   } catch {
     // executionCtx not available in test, skip