- Extracted fetch mocking logic into reusable `hookFetch()` utility function with middleware-style handler pattern.
- Replaced manual `globalThis.fetch` assignment and restoration across 10 test files with `hookFetch()` calls using `using` statement for automatic cleanup.
- Implemented Disposable pattern with Symbol.dispose for fetch hook resource management, eliminating try-finally blocks.
- Exported `hookFetch` from utils public API to enable consistent fetch mocking across packages.
- Added `authServerUrl` field to `AuthDetectionResult` to capture MCP OAuth server metadata.
- Added `extractMcpAuthServerUrl()` function to parse and validate `Mcp-Auth-Server` header URLs from OAuth errors.
- Enhanced `discoverOAuthEndpoints()` to accept optional `authServerUrl` parameter and query `/.well-known/oauth-protected-resource` endpoint.
- Improved OAuth metadata extraction to handle multiple `clientId` field variations (`clientId`, `default_client_id`, `public_client_id`).
- Extracted metadata parsing logic into reusable `findEndpoints()` helper function supporting multiple OAuth metadata formats.
- Added comprehensive test coverage for OAuth endpoint discovery, header parsing, and error validation.
Fixes#235
can1357