fix(cli): handle malformed MCP config files in remove detection

[fahreddinozcan]

Summary

ctx7 remove crashed with an unhandled SyntaxError whenever any of the agents' well-known JSON config paths contained unparseable content (e.g. a hand-edited ~/.claude.json with a stray comma). readJsonConfig only caught file-read errors, not JSON.parse errors, and the detection path didn't wrap it.

This patch wraps the readJsonConfig call in hasMcpConfig with a try/catch that logs a warning naming the offending file and parse error, then skips that agent for detection. Detection continues for the remaining agents and the user gets an actionable line instead of a stack trace.

readJsonConfig itself stays strict so the write paths (setup, uninstallMcp) keep surfacing failures through their existing per-agent results-table error handling — silently swallowing parse errors there could risk overwriting a real-but-malformed user config.

Before

$ npx ctx7 remove
SyntaxError: Expected double-quoted property name in JSON at position 703 (line 21 column 25)
    at JSON.parse ()
    at readJsonConfig (...)
    at async hasMcpConfig (...)
    ...

After

$ npx ctx7 remove
⚠ Skipped /Users/.../.claude.json: could not parse (Expected double-quoted property name in JSON at position 703 (line 21 column 25))
⚠ No Context7 setup detected. Pass --claude, --cursor, --opencode, --codex, or --gemini.

Reported in #2561 where the user's pre-existing malformed ~/.claude.json (unrelated to ctx7) caused remove to crash with no indication of which file was at fault.

[linear]

CTX7-1615 handle mcp config detection errors in remove command