feat: Implement AI Knowledge Sync Utilities and RAGFlow Service

- Added `aiknowledge_sync_utils.py` for provider-agnostic synchronization logic for CAIKnowledge entities, supporting both xAI and RAGFlow.
- Introduced lifecycle management for CAIKnowledge entities including states: new, active, paused, and deactivated.
- Implemented change detection using Blake3 hash for efficient document synchronization.
- Created `ragflow_service.py` to handle dataset and document management with RAGFlow API.
- Added daily cron job in `aiknowledge_daily_cron_step.py` to synchronize active CAIKnowledge entities with unclean or failed statuses.
- Developed `aiknowledge_sync_event_step.py` to process synchronization events from webhooks and cron jobs.

pyproject.toml

@@ -17,7 +17,8 @@ dependencies = [
     "asyncpg>=0.29.0",  # PostgreSQL async driver for calendar sync
     "google-api-python-client>=2.100.0",  # Google Calendar API
     "google-auth>=2.23.0",  # Google OAuth2
-    "backoff>=2.2.1",  # Retry/backoff decorator
+    "backoff>=2.2.1",
+    "ragflow-sdk>=0.24.0",  # RAGFlow AI Provider
     "langchain>=0.3.0",  # LangChain framework
     "langchain-xai>=0.2.0",  # xAI integration for LangChain
     "langchain-core>=0.3.0",  # LangChain core