Pin mcp below 2.0 to fix fresh installs

[oleksandr-nc]

Summary

pyproject.toml declared mcp[cli]>=1.20 with no upper bound. mcp 2.0.0 (released 2026-07-28) removed mcp.server.fastmcp: FastMCP is now mcp.server.mcpserver.MCPServer, and other APIs changed. A fresh install now resolves mcp 2.2.0, and the server fails on startup at from mcp.server.fastmcp import FastMCP in src/nc_mcp_server/server.py:

ModuleNotFoundError: No module named 'mcp.server.fastmcp'. This is mcp 2.x, where FastMCP was renamed to MCPServer ...

In 2.x, mcp/server/fastmcp.py is only a stub that raises this error (same in v2.1.1 and v2.2.0), so there is no compatibility path without code changes.

This PR caps the requirement at mcp[cli]>=1.20,<2. It is the minimal unblock; migrating to the 2.x MCPServer API is separate work.

Worth knowing

• PyPI installs stay broken until a release. The published nc-mcp-server 0.7.0 has the same unbounded requirement, so pip install nc-mcp-server pulls mcp 2.2.0 today. A patch release (e.g. 0.7.1) is needed after merge; publish.yml runs when a GitHub release is published.
• CI hasn't caught this yet. The unit-test workflow installs with pip install -e ".[dev]", and its last run (2026-07-26, on Bump the ci-dependencies group across 1 directory with 4 updates #57) was two days before mcp 2.0.0 shipped. Any new run without this cap would install mcp 2.x.

Test plan

• uv pip compile of mcp[cli]>=1.20 resolves mcp==2.2.0; with <2 it resolves mcp==1.30.0
• With mcp 1.29.1 installed, nc_mcp_server.server imports and the unit tests run locally on Windows: 93 passed; the 11 failures are Windows-specific symlink/FIFO/os.O_NOFOLLOW tests, unrelated to this change
• CI green (unit tests on Python 3.12–3.14)

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