feat(core): add localization completeness checks (#73)

[i-afaqrashid]

Closes #73.

What

Adds opt-in checks.localization:

checks: {
  localization: {
    locales: ["en", "fr", "de"],
    localeField: "locale",        // path in document.data; default "locale"
    groupField: "translationKey", // default: document.uid
    types: ["page", "article"],   // optional
    severity: "warning",
  },
}

Groups published documents by ${type}:${groupKey} and emits CMS-LOCALE-MISSING for any group not published in every configured locale.

Behavior

• Only published documents count toward a locale being present, so a translation that exists only as a draft is reported as missing (consistent with the status-aware direction).
• groupField defaults to document.uid (common when locales share a slug); override it for setups that link translations by a shared id.
• Documents with no locale value are ignored, so non-localized types never false-positive. types narrows further.
• Adapter-agnostic: locale and group key are read from document.data, no per-adapter changes. Adds a localization check group for --only/--skip and a localization group in HTML/JUnit output.

Why

Locale parity is on the 2026 headless-SEO checklist and was a tracked feature request. A page published in one locale but missing in another is a silent gap that hurts international SEO and UX.

How verified

• New scan tests: draft-only locale flagged; all-published silent; no-locale docs ignored; --skip localization respected.
• New config-schema test (accepts valid, rejects empty locales).
• pnpm verify green (213 tests).

Refs improvements/36.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
cms-lab-site	Ready	Preview, Comment	May 29, 2026 9:06am