kgom-ga-mcp — endpoints:
  GET  /health         → health + GA-koppeling status
  GET  /auth           → start GA-koppeling (eenmalig, laag 2)
  GET  /oauth/callback → GA OAuth redirect-target
  GET  /authorize      → start MCP-client OAuth (claude.ai, laag 1)
  GET  /callback       → Google login redirect-target
  POST /mcp            → MCP JSON-RPC (Bearer token vereist)
  GET  /sse            → MCP SSE (Bearer token vereist)