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.

services/xai_service.py

@@ -552,3 +552,34 @@ class XAIService:
         normalized = mime_type.lower().strip()
 
         return normalized in supported_types
+
+    async def get_collection_by_name(self, name: str) -> Optional[Dict]:
+        """
+        Sucht eine Collection nach Name.
+        Ruft alle Collections auf (Management API listet sie auf).
+
+        GET https://management-api.x.ai/v1/collections
+
+        Returns:
+            Collection dict oder None wenn nicht gefunden.
+        """
+        self._log(f"🔍 Looking up collection by name: {name}")
+        session = await self._get_session()
+        url = f"{XAI_MANAGEMENT_URL}/v1/collections"
+        headers = {"Authorization": f"Bearer {self.management_key}"}
+
+        async with session.get(url, headers=headers) as response:
+            if response.status not in (200,):
+                raw = await response.text()
+                self._log(f"⚠️  list collections failed ({response.status}): {raw}", level='warn')
+                return None
+            data = await response.json()
+
+        collections = data if isinstance(data, list) else data.get('collections', [])
+        for col in collections:
+            if col.get('collection_name') == name or col.get('name') == name:
+                self._log(f"✅ Collection found: {col.get('collection_id') or col.get('id')}")
+                return col
+
+        self._log(f"⚠️  Collection not found by name: {name}", level='warn')
+        return None