feat(frontend): replace inline sync progress with SyncModal

GarminConnection.tsx no longer polls sync status itself or renders any
inline "syncing.../last sync..." text -- SyncModal (previous commit) is
now the only place sync progress and results are shown. Auth-status
polling is simplified to a fixed interval now that it no longer needs
to speed up while a sync is running.

frontend/src/components/GarminConnection.tsx

@@ -1,49 +1,28 @@
-import { useEffect, useRef, useState } from "react";
+import { useEffect, useState } from "react";
 import { api } from "../api/client";
-import type { AuthResponse, SyncStatus } from "../types/api";
-
-function syncProgressLabel(status: SyncStatus): string {
-  const { detail_fill_progress: fill, activities_pending_details: pending } = status;
-  if (fill.Total > 0) {
-    // pending includes the current batch, so subtract what's already
-    // counted in this batch's Total to avoid double-counting the "beyond
-    // this batch" remainder.
-    const beyondBatch = Math.max(0, pending - (fill.Total - fill.Done));
-    return `syncing: ${fill.Done}/${fill.Total} activities${beyondBatch > 0 ? ` (+${beyondBatch} more queued)` : ""}`;
-  }
-  return "syncing...";
-}
+import type { AuthResponse } from "../types/api";
+import { SyncModal } from "./SyncModal";
 
 export function GarminConnection({ onBeforeConnect }: { onBeforeConnect?: () => Promise<void> }) {
   const [auth, setAuth] = useState<AuthResponse | null>(null);
   const [code, setCode] = useState("");
   const [busy, setBusy] = useState(false);
   const [error, setError] = useState<string | null>(null);
-  const [syncStatus, setSyncStatus] = useState<SyncStatus | null>(null);
   // There's no real Garmin logout -- the backend session just sits idle.
   // "Disconnect" only hides that and shows Connect again locally; a real
   // login (connect()) clears it.
   const [disconnected, setDisconnected] = useState(false);
+  const [showSyncModal, setShowSyncModal] = useState(false);
 
-  function refreshStatus() {
-    api.authStatus().then(setAuth).catch((e) => setError(String(e)));
-    api.syncStatus().then(setSyncStatus).catch(() => {});
-  }
-
-  // Poll faster while a sync is actually running, so progress feels live;
-  // back off to a relaxed interval the rest of the time.
-  const syncStatusRef = useRef(syncStatus);
-  syncStatusRef.current = syncStatus;
-
+  // Auth status alone -- sync status is polled by SyncModal itself while
+  // it's open, so this no longer needs the "poll faster while syncing"
+  // dynamic interval it used to have.
   useEffect(() => {
-    refreshStatus();
-    let timeout: ReturnType<typeof setTimeout>;
-    const tick = () => {
-      refreshStatus();
-      timeout = setTimeout(tick, syncStatusRef.current?.in_progress ? 1500 : 6000);
-    };
-    timeout = setTimeout(tick, 1500);
-    return () => clearTimeout(timeout);
+    api.authStatus().then(setAuth).catch((e) => setError(String(e)));
+    const interval = setInterval(() => {
+      api.authStatus().then(setAuth).catch(() => {});
+    }, 6000);
+    return () => clearInterval(interval);
   }, []);
 
   async function connect() {
@@ -83,7 +62,7 @@ export function GarminConnection({ onBeforeConnect }: { onBeforeConnect?: () =>
     setError(null);
     try {
       await api.syncRun();
-      refreshStatus();
+      setShowSyncModal(true);
     } catch (e) {
       setError(String(e));
     } finally {
@@ -174,20 +153,9 @@ export function GarminConnection({ onBeforeConnect }: { onBeforeConnect?: () =>
 
       {!disconnected && auth?.message && <p className="garmin-connection-message">{auth.message}</p>}
 
-      {/* Full-width so a long "last sync"/pending-details message has room
-          to breathe, instead of being squeezed next to the status dot. */}
-      {status === "authenticated" && syncStatus?.in_progress && (
-        <p className="garmin-connection-message">{syncProgressLabel(syncStatus)}</p>
-      )}
-      {status === "authenticated" && syncStatus?.last_run && !syncStatus.in_progress && (
-        <p className="garmin-connection-message">
-          last sync: {syncStatus.last_run.Status} ({syncStatus.last_run.ActivitiesFetched} activities)
-          {syncStatus.activities_pending_details > 0 &&
-            ` — ${syncStatus.activities_pending_details} still need details, click Sync now again`}
-        </p>
-      )}
-
       {error && <p className="error">{error}</p>}
+
+      {showSyncModal && <SyncModal onClose={() => setShowSyncModal(false)} />}
     </div>
   );
 }