feat(automation): add daily briefing preset and cron backup scheduling

src/daemon/index.ts

@@ -2,6 +2,7 @@
 import { resolve } from 'path';
 import { homedir } from 'os';
 import { mkdirSync } from 'fs';
+import { Cron } from 'croner';
 
 // ── Config & Types ──
 import type { Config } from '../config/index.js';
@@ -106,7 +107,8 @@ export async function startDaemon(config: Config, options?: StartDaemonOptions):
 
   if (config.backup.enabled) {
     const backupIntervalMs = parseDuration(config.backup.interval);
-    if (!backupIntervalMs) {
+    const backupSchedule = config.backup.schedule?.trim();
+    if (!backupSchedule && !backupIntervalMs) {
       console.warn(`Backup enabled but interval is invalid: ${config.backup.interval}`);
     } else {
       let backupRunning = false;
@@ -129,11 +131,44 @@ export async function startDaemon(config: Config, options?: StartDaemonOptions):
         }
       };
 
-      const backupInterval = setInterval(() => {
-        void runScheduledBackup();
-      }, backupIntervalMs);
-      lifecycle.onShutdown(async () => { clearInterval(backupInterval); });
-      console.log(`Backup scheduler enabled (${config.backup.interval})`);
+      let backupCron: Cron | undefined;
+      let backupInterval: ReturnType<typeof setInterval> | undefined;
+
+      if (backupSchedule) {
+        try {
+          backupCron = new Cron(backupSchedule, { paused: false }, () => {
+            void runScheduledBackup();
+          });
+          console.log(`Backup scheduler enabled (cron: ${backupSchedule})`);
+        } catch (error) {
+          const message = error instanceof Error ? error.message : String(error);
+          console.warn(`Backup cron schedule is invalid (${backupSchedule}): ${message}`);
+        }
+      }
+
+      if (!backupCron && backupIntervalMs) {
+        backupInterval = setInterval(() => {
+          void runScheduledBackup();
+        }, backupIntervalMs);
+        console.log(`Backup scheduler enabled (interval: ${config.backup.interval})`);
+      }
+
+      if (!backupCron && !backupInterval) {
+        console.warn('Backup scheduler disabled: no valid backup.schedule or backup.interval');
+      } else {
+        if (config.backup.run_on_start) {
+          void runScheduledBackup();
+        }
+
+        lifecycle.onShutdown(async () => {
+          if (backupCron) {
+            backupCron.stop();
+          }
+          if (backupInterval) {
+            clearInterval(backupInterval);
+          }
+        });
+      }
     }
   }