🔄 Revert: Restored fast loading screen and manual-only sync per user request

frontend/components/GlobalSync.tsx

@@ -17,29 +17,10 @@ export default function GlobalSync({ onComplete }: { onComplete: () => void }) {
   ];
 
   useEffect(() => {
-    let syncDone = false;
     let currentMsg = 0;
     
-    const performSync = async () => {
-      try {
-        const { syncDatabase } = await import("../lib/api");
-        console.log("[GlobalSync] Starting background sync...");
-        await syncDatabase();
-        console.log("[GlobalSync] Sync finished successfully.");
-      } catch (e) {
-        console.error("[GlobalSync] Sync failed:", e);
-      } finally {
-        syncDone = true;
-      }
-    };
-
-    performSync();
-
     const interval = setInterval(() => {
       setProgress(prev => {
-        // If sync is not done, slow down near 90%
-        if (!syncDone && prev >= 90) return 90;
-        
         if (prev >= 100) {
           clearInterval(interval);
           setTimeout(onComplete, 500);