fix(mcp): stop idle OAuth callback server

[rekram1-node]

Summary

• stop the MCP OAuth callback listener after the final callback succeeds, returns a provider error, is cancelled, or times out
• register authenticate callbacks before listener startup and serialize listener start/stop transitions so concurrent flows cannot strand or lose the listener
• preserve configured callback ports and redirect paths while covering lifecycle and concurrency behavior with focused tests

Tests

• bun test test/mcp/oauth-callback.test.ts test/mcp/oauth-browser.test.ts test/mcp/lifecycle.test.ts --timeout 30000 (45 pass)
• bun test test/mcp/oauth-callback.test.ts --timeout 30000 after formatting (11 pass)

Closes #23568
Closes #23563
Related to #28567
Related to #30888