- Add AuthClientID and AuthClientFromMCP fields to edition Hooks, allowing overlays to override the default OAuth client ID and route auth through MCP endpoints.
- Introduce token marker file (token.json) mechanism so the host application in embedded mode can detect authentication state without accessing the keychain.
- Update SaveTokenData/DeleteTokenData to write/remove the marker file when running in embedded mode.
- Update ClientID() and IsClientIDFromMCP() to respect edition overrides.