feat: auto-prune stale session artifacts on startup + daily

Session files (JSONLs, debug logs, todos, telemetry, group logs) accumulate
unboundedly — especially from daily cron tasks. This adds a cleanup script
that prunes old artifacts while protecting active sessions (read from DB),
and wires it into the main process on a 24h interval.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/index.ts

@@ -61,6 +61,7 @@ import {
   loadSenderAllowlist,
   shouldDropMessage,
 } from './sender-allowlist.js';
+import { startSessionCleanup } from './session-cleanup.js';
 import { startSchedulerLoop } from './task-scheduler.js';
 import { Channel, NewMessage, RegisteredGroup } from './types.js';
 import { logger } from './logger.js';
@@ -746,6 +747,7 @@ async function main(): Promise<void> {
       }
     },
   });
+  startSessionCleanup();
   queue.setProcessMessagesFn(processGroupMessages);
   recoverPendingMessages();
   startMessageLoop().catch((err) => {

src/session-cleanup.ts

@@ -0,0 +1,25 @@
+import { execFile } from 'child_process';
+import path from 'path';
+
+import { logger } from './logger.js';
+
+const CLEANUP_INTERVAL = 24 * 60 * 60 * 1000; // 24 hours
+const SCRIPT_PATH = path.resolve(process.cwd(), 'scripts/cleanup-sessions.sh');
+
+function runCleanup(): void {
+  execFile('/bin/bash', [SCRIPT_PATH], { timeout: 60_000 }, (err, stdout) => {
+    if (err) {
+      logger.error({ err }, 'Session cleanup failed');
+      return;
+    }
+    const summary = stdout.trim().split('\n').pop();
+    if (summary) logger.info(summary);
+  });
+}
+
+export function startSessionCleanup(): void {
+  // Run once at startup (delayed 30s to not compete with init)
+  setTimeout(runCleanup, 30_000);
+  // Then every 24 hours
+  setInterval(runCleanup, CLEANUP_INTERVAL);
+}