CLI error messages are parsed as Rich markup, so skillspector mcp drops [mcp] from its install hint #885

On main at 95a52d8, the CLI prints exception text with err_console.print(f"[red]Error:[/red] {e}") in cli.py (for example lines 396, 699, 743, 908 and 3413), so any brackets in the message are read as Rich markup.

Repro in a fresh venv with pip install git+https://github.com/NVIDIA/SkillSpector:

• skillspector mcp prints Install it with: pip install 'skillspector'. The message in mcp_server.py:268 says skillspector[mcp], and following the printed advice doesn't install the extra.
• skillspector scan "skills[old]/demo" reports Cannot determine input type for: skills/demo.
• skillspector scan "nope[/x]" ends in a MarkupError traceback instead of the usual exit-2 error.

#725 fixed the same class for terminal reports (terminal_text.visible_terminal_text) and #734 for batch output; the CLI error lines weren't covered.

A fix would escape the interpolated text with rich.markup.escape at each of those call sites, with a CLI test per case above. Would a PR for that be welcome?