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>

frontend/src/pages/ProfilePage.jsx

@@ -119,6 +119,8 @@ export default function ProfilePage() {
   const [gcSaved, setGcSaved] = useState(false)
   const [gcError, setGcError] = useState('')
   const [gcSyncing, setGcSyncing] = useState(false)
+  const syncPollRef = useRef(null)
+  useEffect(() => () => { if (syncPollRef.current) clearInterval(syncPollRef.current) }, [])
   useEffect(() => {
     if (garminConfig?.connected) {
       setGcForm(f => ({
@@ -153,12 +155,37 @@ export default function ProfilePage() {
     setGcSyncing(true)
     try {
       await api.post('/garmin-sync/trigger')
-      setTimeout(() => { refetchGarmin(); setGcSyncing(false) }, 3000)
-    } catch (e) {
+      // Poll every 2s: wait until we've seen an in-progress status, then wait for terminal
+      let seenInProgress = false
+      syncPollRef.current = setInterval(async () => {
+        const result = await refetchGarmin()
+        const status = result.data?.last_sync_status ?? ''
+        const terminal = status.startsWith('OK') || status.startsWith('Partial') || status.startsWith('Auth error')
+        if (!terminal) seenInProgress = true
+        if (seenInProgress && terminal) {
+          clearInterval(syncPollRef.current)
+          syncPollRef.current = null
+          setGcSyncing(false)
+        }
+      }, 2000)
+      // Safety: stop polling after 10 minutes regardless
+      setTimeout(() => {
+        if (syncPollRef.current) { clearInterval(syncPollRef.current); syncPollRef.current = null }
+        setGcSyncing(false)
+      }, 600000)
+    } catch {
       setGcSyncing(false)
     }
   }
 
+  const syncProgressPct = status => {
+    if (!status) return 5
+    if (status.startsWith('Connecting')) return 10
+    if (status.startsWith('Syncing activities')) return 35
+    if (status.startsWith('Syncing wellness')) return 70
+    return 5
+  }
+
   // PocketID config
   const [pidForm, setPidForm] = useState({ issuer: '', client_id: '', client_secret: '' })
   const [pidSaved, setPidSaved] = useState(false)
@@ -389,6 +416,20 @@ export default function ProfilePage() {
             </>
           )}
         </div>
+
+        {gcSyncing && (
+          <div className="space-y-1.5">
+            <div className="h-1.5 bg-gray-800 rounded-full overflow-hidden">
+              <div
+                className="h-full bg-blue-500 rounded-full transition-all duration-700"
+                style={{ width: `${syncProgressPct(garminConfig?.last_sync_status)}%` }}
+              />
+            </div>
+            <p className="text-xs text-blue-400">
+              {garminConfig?.last_sync_status || 'Starting sync…'}
+            </p>
+          </div>
+        )}
       </Section>
 
       {/* PocketID — admin only */}