Add interactive skill MCP removal

[artjen]

Summary

• Add interactive ucode skill remove --mcp behavior.
• Support removal from all agents or selected --agents.
• Protect administrator-managed schemas and retain the schema-less utility connection.
• Soft-deprecate ucode configure skills while preserving compatibility.

Part 4 of the skill CLI series. Builds on #468.

Testing

• uv run ruff check .
• uv run ty check src/
• uv run pytest tests/test_skills_download.py tests/test_mcp.py tests/test_cli.py -q

---

_{Stack created with GitHub Stacks CLI • Give Feedback 💬}