fix: admins bypass RBAC channel filter for doc search

feat: add confluence/slack search tools, chat history, cloud Qdrant support, sync trigger fixes

Implement anomaly detection and forecasting features

feat: enhance analytics API with freshness computation and coverage gaps endpoint

feat: RBAC foundation — workspaces, channels, role-based access

feat: add Zustand stores for filters and UI state management

Add agent and ingestion modules for Enterprise Knowledge Copilot