chore(obs): add lightweight console logs for scheduler and push

Log scheduler ticks, refresh requests, dedupe skips by device id,
push attempt/success with token hints, and push failures without
extra sensitive fields.

src/scheduler.ts

@@ -8,12 +8,13 @@ export function startScheduler(): void {
 
   intervalId = setInterval(async () => {
     try {
+      console.log("[Scheduler] Checking devices...");
       const devices = await db.getAll();
       for (const d of devices) {
         await sendPushToDevice(d.fcmToken);
       }
     } catch (err) {
-      console.error("scheduler tick failed", err);
+      console.error("[Scheduler] Tick failed", err);
     }
   }, 5 * 60 * 1000);
 }