Enhance health status check to handle malformed last_run values and improve logging

src/api/gradio_main.py

@@ -53,10 +53,19 @@ def get_health_status():
             if os.path.exists(last_run_file):
                 with open(last_run_file, 'r') as f:
                     last_run_str = f.read().strip()
-                    last_run = datetime.strptime(last_run_str, '%Y-%m-%d %H:%M:%S')
-                    time_since_last_run = (datetime.now() - last_run).total_seconds()
-                    scheduler_running = time_since_last_run < 2700  # 45 minutes
-                    last_run_time = last_run_str
+                    if last_run_str:
+                        try:
+                            last_run = datetime.strptime(last_run_str, '%Y-%m-%d %H:%M:%S')
+                            time_since_last_run = (datetime.now() - last_run).total_seconds()
+                            scheduler_running = time_since_last_run < 2700  # 45 minutes
+                            last_run_time = last_run_str
+                        except Exception:
+                            logger.debug("Malformed last_run value: %s", last_run_str)
+                            scheduler_running = False
+                            last_run_time = "Unknown"
+                    else:
+                        scheduler_running = False
+                        last_run_time = "Unknown"
         except Exception as e:
             logger.warning(f"Could not check scheduler status: {e}")