fix: bound MCP extra to supported major version

[koriyoshi2041]

Problem

Fresh skillspector[mcp] installs resolve MCP 2.x, which removed mcp.server.fastmcp. The install succeeds, but the server fails at initialization and incorrectly reports that the optional dependency is missing. Fixes #333.

Fix

• constrain the MCP extra to the supported 1.x line
• regenerate the lockfile
• distinguish an absent mcp package from an installed package missing the expected FastMCP module
• cover the incompatible-install diagnostic

Test

• uv run pytest -q tests/unit/test_mcp_server.py (10 passed, including stdio initialize/list-tools)
• uv run ruff check src/skillspector/mcp_server.py tests/unit/test_mcp_server.py
• uv run ruff format --check src/skillspector/mcp_server.py tests/unit/test_mcp_server.py
• git diff --check

Risk

Low. This deliberately holds the optional server integration on MCP 1.x until SkillSpector migrates to the 2.x API; users that force an incompatible install now receive an accurate error instead of a missing-extra message.

[rng1995]

[Automated SkillSpector Review]

Approved. Bounding the optional MCP dependency below v2 keeps the currently supported FastMCP import contract explicit, and the improved import error distinguishes an absent package from an incompatible installed layout. The focused MCP suite passed (10 tests), as did Ruff lint and format checks.