- Add a test MCP server (test_server.py) for integration testing
- Add 14 integration tests that hit a real local MCP server over HTTP
- Add trusted_origins support to MCPClient for localhost/internal servers
- MCPToolBlock now trusts the user-configured server URL by default
- Add local conftest.py to avoid SpinTestServer overhead for MCP tests
Test results: 34 unit tests + 14 integration tests = 48 total, all passing