Add sync progress bar; change auto-sync to every 30 minutes

Backend:
- Change beat schedule from 3600s (hourly) to 1800s (30 minutes)
- Emit intermediate last_sync_status DB commits at each phase of
  sync_garmin_connect_user ("Connecting to Garmin...", "Syncing activities...",
  "Syncing wellness data...") so the frontend can reflect live progress.
  Snapshot config fields upfront to avoid reading expired ORM attrs after commits.

Frontend (ProfilePage):
- Replace blind 3-second timeout with 2s polling loop that reads the live
  last_sync_status from /garmin-sync/config after triggering a sync.
- Wait until an in-progress status is observed before declaring completion,
  avoiding a false-finish on the previous terminal status.
- Show an animated progress bar that advances through the sync phases with
  the current status text below it. Safety timeout stops polling after 10 min.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/workers/tasks.py

@@ -23,9 +23,9 @@ celery_app.conf.update(
     task_track_started=True,
     worker_prefetch_multiplier=1,
     beat_schedule={
-        "sync-garmin-connect-hourly": {
+        "sync-garmin-connect": {
             "task": "sync_all_garmin_connect",
-            "schedule": 3600.0,  # every hour
+            "schedule": 1800.0,  # every 30 minutes
         },
     },
 )
@@ -481,8 +481,20 @@ def sync_garmin_connect_user(user_id: int):
         if not cfg or not cfg.sync_enabled:
             return {"status": "skipped"}
 
+        # Snapshot config values before any intermediate commits (commits expire ORM attrs)
+        email        = cfg.email
+        password_enc = cfg.password_enc
+        token_store  = cfg.token_store
+        last_sync_at = cfg.last_sync_at
+        sync_acts    = cfg.sync_activities
+        sync_well    = cfg.sync_wellness
+        lookback     = cfg.sync_lookback_days if cfg.sync_lookback_days is not None else 30
+
+        cfg.last_sync_status = "Connecting to Garmin..."
+        db.commit()
+
         try:
-            garmin, new_token = authenticate_garmin(cfg.email, cfg.password_enc, cfg.token_store)
+            garmin, new_token = authenticate_garmin(email, password_enc, token_store)
         except Exception as exc:
             cfg.last_sync_at = datetime.now(timezone.utc)
             cfg.last_sync_status = f"Auth error: {exc}"
@@ -491,25 +503,30 @@ def sync_garmin_connect_user(user_id: int):
 
         if new_token:
             cfg.token_store = new_token
+            db.commit()
 
         activities_queued = 0
         wellness_days = 0
         errors = []
 
-        if cfg.sync_activities:
+        if sync_acts:
+            cfg.last_sync_status = "Syncing activities..."
+            db.commit()
             try:
                 activities_queued = sync_activities(
-                    garmin, user_id, cfg.last_sync_at, db, settings.file_store_path,
-                    lookback_days=cfg.sync_lookback_days if cfg.sync_lookback_days is not None else 30,
+                    garmin, user_id, last_sync_at, db, settings.file_store_path,
+                    lookback_days=lookback,
                 )
             except Exception as exc:
                 errors.append(f"activities: {exc}")
 
-        if cfg.sync_wellness:
+        if sync_well:
+            cfg.last_sync_status = "Syncing wellness data..."
+            db.commit()
             try:
                 wellness_days = sync_wellness(
-                    garmin, user_id, cfg.last_sync_at, db,
-                    lookback_days=cfg.sync_lookback_days if cfg.sync_lookback_days is not None else 90,
+                    garmin, user_id, last_sync_at, db,
+                    lookback_days=lookback,
                 )
             except Exception as exc:
                 errors.append(f"wellness: {exc}")