fix:performance improvements
- app.py: Pre-warm AI connectors at module load and in lifespan
- aicoreModelRegistry.py: Connector discovery cache, getAvailableModels cache, bulk RBAC, eager prewarm
- connectorDbPostgre.py: Connector cache, contextvars for userId, eviction (max 32)
- chatbot: Uses _get_cached_connector, Service center integration, BillingService exceptions, BillingService exceptions instead of direct imports
- interfaceDbApp.py: Uses _get_cached_connector
- interfaceDbManagement.py: Uses _get_cached_connector
- security/rbac.py: Adds checkResourceAccessBulk