fix(home-scope): infrastructure-security and mcp-config read $HOME only when opted in

[joepetjr]

What

infrastructure-security and mcp-config now read the operator's $HOME only with --include-home-skills. They go through src/lib/home-scope.js like every other home-reading check (RS-10).

• infrastructure-security §5/§6: ~/.claude/settings.json and settings.local.json drop out of settingsPaths unless home scope is on. Project .claude/settings.json is always read.
• mcp-config: with home scope off, the scan uses repoMcpPaths(cwd) (the committed base: 'cwd' configs) instead of mcpConfigPaths(cwd, homedir). checkClaudeSettings gets null for home, so home enableAllProjectMcpServers and home hooks no longer change a project's verdict.

Why

The same tree scored 65 with a bare runner HOME and 81 with a populated one. A project score that depends on who ran the scan contradicts the CLI's own promise that "home findings do not affect project scores unless --include-home-skills is set."

Tests

• New, red before the fix:
  • test/infrastructure-security.test.js: identical deny-list findings and score for a bare vs a populated home; opting in reads home; project settings are always read.
  • test/home-scope.test.js: home MCP configs are N/A without the flag; home auto-approve leaves the project findings unchanged; opting in reads home.
• Opted into home scope: five existing tests (Codex TOML, Goose YAML, Cline, two Zed) wrote their fixture only under $HOME, so they now pass includeHomeSkills: true. Their assertions are unchanged.
• Results:
  • npm test: 2249 passed. The 3 that failed are timing tests (performance ×2, the RS-32 --quiet 10s timeout) at load average 51. Run alone, those two files pass 19/19.
  • npm run verify:docs: OK.
  • npm run test:fixture: 5 passed.

Not in this PR

Sandbox-gate detection is still a substring match on the hooks JSON (audit R3). Making it structural, counting it only as a PreToolUse hook command, is a separate unit.