Fix gather extract: file-based tasks (multi-worker safe), correct status completed check

app.py.final

@@ -31,7 +31,41 @@ if not os.path.exists(TEMP_DIR):
     os.makedirs(TEMP_DIR)
 
 # Global task store
-TASKS = {}
+import threading
+_task_lock = threading.Lock()
+_TASK_FILE = '/tmp/seismic_tasks.json'
+
+def _load_tasks():
+    try:
+        with open(_TASK_FILE) as f:
+            return json.load(f)
+    except:
+        return {}
+
+def _save_tasks(tasks):
+    with open(_TASK_FILE, 'w') as f:
+        json.dump(tasks, f)
+
+class TasksProxy:
+    def get(self, key, default=None):
+        return _load_tasks().get(key, default)
+    def __setitem__(self, key, value):
+        with _task_lock:
+            tasks = _load_tasks()
+            tasks[key] = value
+            _save_tasks(tasks)
+    def __getitem__(self, key):
+        return _load_tasks()[key]
+    def __contains__(self, key):
+        return key in _load_tasks()
+    def pop(self, key, *args):
+        with _task_lock:
+            tasks = _load_tasks()
+            result = tasks.pop(key, *args)
+            _save_tasks(tasks)
+            return result
+
+TASKS = TasksProxy()
 
 # ========== UTILITY FUNCTIONS ==========