feat: Implement AI Knowledge Sync Utilities and Event Handlers

- Added AIKnowledgeActivationStatus and AIKnowledgeSyncStatus enums to models.py for managing activation and sync states.
- Introduced AIKnowledgeSync class in aiknowledge_sync_utils.py for synchronizing CAIKnowledge entities with XAI Collections, including collection lifecycle management, document synchronization, and metadata updates.
- Created a daily cron job (aiknowledge_full_sync_cron_step.py) to perform a full sync of CAIKnowledge entities.
- Developed an event handler (aiknowledge_sync_event_step.py) to synchronize CAIKnowledge entities with XAI Collections triggered by webhooks and cron jobs.
- Implemented a webhook handler (aiknowledge_update_api_step.py) to receive updates from EspoCRM for CAIKnowledge entities and enqueue sync events.
- Enhanced xai_service.py with methods for collection management, document listing, and metadata updates.

services/models.py

@@ -68,6 +68,40 @@ class SalutationType(str, Enum):
     FIRMA = ""
 
 
+class AIKnowledgeActivationStatus(str, Enum):
+    """Activation status for CAIKnowledge collections"""
+    NEW = "new"                    # Collection noch nicht in XAI erstellt
+    ACTIVE = "active"              # Collection aktiv, Sync läuft
+    PAUSED = "paused"              # Collection existiert, aber kein Sync
+    DEACTIVATED = "deactivated"    # Collection aus XAI gelöscht
+    
+    def __str__(self) -> str:
+        return self.value
+
+
+class AIKnowledgeSyncStatus(str, Enum):
+    """Sync status for CAIKnowledge"""
+    UNCLEAN = "unclean"            # Änderungen pending
+    PENDING_SYNC = "pending_sync"   # Sync läuft (locked)
+    SYNCED = "synced"              # Alles synced
+    FAILED = "failed"              # Sync fehlgeschlagen
+    
+    def __str__(self) -> str:
+        return self.value
+
+
+class JunctionSyncStatus(str, Enum):
+    """Sync status for junction tables (CAIKnowledgeCDokumente)"""
+    NEW = "new"
+    UNCLEAN = "unclean"
+    SYNCED = "synced"
+    FAILED = "failed"
+    UNSUPPORTED = "unsupported"
+    
+    def __str__(self) -> str:
+        return self.value
+
+
 # ========== Advoware Models ==========
 
 class AdvowareBeteiligteBase(BaseModel):