修复Celery任务注册问题

- 在tasks/__init__.py中导入media_learning任务
- 在ops/__init__.py中注册media_learning任务到Celery应用
- 修复KeyError: 'media_learning_by_document'错误

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/knowledge/tasks/__init__.py

@@ -2,4 +2,5 @@
 
 # Import tasks for Celery discovery
 # Note: We import the specific tasks, not * to avoid circular imports
-from .advanced_learning import advanced_learning_by_document, batch_advanced_learning
+from .advanced_learning import advanced_learning_by_document, batch_advanced_learning
+from .media_learning import media_learning_by_document, media_learning_batch

apps/ops/__init__.py

@@ -19,3 +19,15 @@ try:
     celery_app.register_task(batch_advanced_learning)
 except ImportError:
     pass
+
+# Import and register media learning tasks
+try:
+    from knowledge.tasks.media_learning import (
+        media_learning_by_document,
+        media_learning_batch
+    )
+    # Register tasks with the celery app
+    celery_app.register_task(media_learning_by_document)
+    celery_app.register_task(media_learning_batch)
+except ImportError:
+    pass