- Create mcpTokenStore: in-memory token storage keyed by normalized server URL
with automatic expiry checking
- Create mcpOAuthService: full OAuth 2.1 + PKCE flow implementation
- Protected Resource Metadata discovery (RFC 9728)
- Authorization Server Metadata fetch (RFC 8414)
- Dynamic Client Registration (RFC 7591) when no static client ID
- PKCE S256 code challenge generation
- Local HTTP callback server for auth code receipt
- Browser-based consent via Electron shell.openExternal
- Authorization code to token exchange
- Add startSessionMcpAuth IPC channel and handler to trigger OAuth flow
- Inject stored OAuth tokens as Authorization headers in buildRunTurnToolingConfig
- Update McpAuthBanner with 'Authenticate in browser' button and loading state
- Add tests for token store (7 tests) and token injection (3 tests)
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
