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

fix: enhance admin functionality and error handling in ingestion and analytics processes

feat: channel RBAC through ingest, graph stream, admin endpoints, email invite

fix: type errors, merge OAuth branch, upgrade BM25Store

feat: implement Google OAuth2 SSO integration with user management and callback handling

User Settings (/settings) — 3 tabs:

feat: add Zustand stores for filters and UI state management