bug fix: last sync time is the lastest file modified in data_cache, change app.py and index.html

app.py

@@ -74,12 +74,19 @@ def get_summary():
     instruments = engine.load_instruments_from_csv('instruments.csv')
     
     results = []
+    latest_mtime = 0  # To track the actual freshest data file
+
     for item in instruments:
         # Update engine target
         engine.symbol = item['symbol'].strip().upper()
         engine.file_path = os.path.join(engine.cache_dir, f"{engine.symbol}.csv")
-        
-        metrics = engine.get_local_metrics()
+        # --- NEW: UPDATE LATEST_MTIME HERE ---
+        if os.path.exists(engine.file_path):
+            file_time = os.path.getmtime(engine.file_path)
+            if file_time > latest_mtime:
+                latest_mtime = file_time
+        # -------------------------------------
+                metrics = engine.get_local_metrics()
         display_name = item.get('name') or engine.symbol
         
         if metrics:
@@ -97,8 +104,17 @@ def get_summary():
                 'last_close': 'N/A',
                 'error': True
             })
-            
-    return jsonify(results)
+    # Format the latest sync time found
+    if latest_mtime > 0:
+        last_mod_time = datetime.fromtimestamp(latest_mtime).strftime('%d/%b %H:%M:%S')
+    else:
+        last_mod_time = "Never"
+
+    return jsonify({
+        "last_sync": last_mod_time,
+        "data": results  # Fixed the 'data_list' syntax error here
+    })
+
 
 @app.route('/api/sync', methods=['POST'])
 def run_sync():