local-ci parity gap: .opencode-plugin's npm ci/typecheck/test has no local-ci counterpart

[jsirish]

Context

Surfaced during PR #48's review (code-reviewer agent, 2026-08-25). .local-ci.json exists explicitly "for local-ci parity" with CI (see chore: add .local-ci.json for local-ci parity (#48) (#23)), but CI's second job (.github/workflows/ci.yml's opencode-plugin job: npm ci → npm run typecheck → npm test inside .opencode-plugin/) has no .local-ci.json equivalent.

Why local-ci's own JS driver doesn't already cover it: it requires a package.json at the repo root (none exists — the OpenCode plugin's package.json lives in .opencode-plugin/), and local-ci's directory discovery prunes dot-directories (-name '.?*' -prune), so .opencode-plugin/ is never scanned even if you ran local-ci against it directly by name.

Suggested fix

Add a fourth custom check to .local-ci.json:

{
  "label": "opencode plugin",
  "run": "cd .opencode-plugin && npm ci && npm run typecheck && npm test"
}

Low priority, not a functional gap (CI still catches it) — just a parity gap between local-ci and what CI actually runs, same class of thing this repo already tracks as worth closing.