fix(mcp): cap the mcp SDK below 2.0 and add a smoke CI matrix

[wnykaza-ui]

Fixes #3.

Commit 1, the pin. mcp/pyproject.toml and mcp/requirements.txt both declared mcp>=1.2.0 with no upper bound. The mcp Python SDK 2.0.0 removed the mcp.server.fastmcp module that mcp/server.py imports at line 56, so any clean install resolves to 2.0.0 and dies on import. Both files now declare mcp>=1.2.0,<2, which keeps the whole 1.x line eligible and blocks 2.x until the server is ported to the new API.

Commit 2, the CI. The repo had no .github directory and nothing ran mcp/smoke.py, which is why an upstream SDK release could break every clean install with no signal. This adds .github/workflows/smoke.yml, a matrix over ubuntu-latest and windows-latest across Python 3.11, 3.12 and 3.13, that installs mcp/requirements.txt and runs the smoke suite. It needs no network and no secrets, so it runs on forks and pull requests without configuration.

Two details make the Windows leg work. Every step runs under bash so $GITHUB_ENV and the heredoc behave identically on both runners. And smoke.py picks its subprocess interpreter with os.environ.get("PYTHON", HERE/".venv"/"bin"/"python"). That fallback is POSIX only and CI never creates a .venv anyway, so a step exports PYTHON from sys.executable before the run. This uses the existing override rather than changing smoke.py, keeping this PR scoped to the dependency bug plus coverage.

A guard step imports mcp.server.fastmcp and asserts the resolved major version is below 2, so the job fails loudly if the cap ever stops holding.

Verification. Fresh python -m venv, pip install -r mcp/requirements.txt with the new pin, resolved mcp 1.29.0 instead of 2.0.0, then ran the suite. The server boots clean, lists all 23 tools and every assertion passes:

TOOL COUNT: 23
ALL ASSERTIONS PASS: True

Exit code 0. Verified on Windows 11 with Python 3.14 using the PYTHON override, which is the same mechanism the Windows CI leg uses. The ModuleNotFoundError was also reproduced directly against mcp==2.0.0 in a throwaway venv to confirm the cause.

Not included here. The Windows .venv/bin/python hardcode in smoke.py line 32 and the three mcp/README.md references are left alone, as is an abi_encode bool coercion finding. Happy to send those as follow ups so this PR stays reviewable.