fix: keep background jobs alive

Add a background job orchestrator that restores profile jobs from saved credentials,
keeps pickup and store-watch schedules alive without UI logins, and exposes job
status via health/admin endpoints.

services/sessionStore.js

@@ -48,6 +48,15 @@ class SessionStore {
     return session;
   }
 
+  getByProfile(profileId) {
+    const key = profileId ? String(profileId) : null;
+    if (!key) {
+      return null;
+    }
+    const id = this.profileIndex.get(key);
+    return id ? this.get(id) : null;
+  }
+
   update(id, patch) {
     const session = this.get(id);
     if (!session) {