[callumalpass]

Summary

• Pin @mdbase-dev/i18n to exactly 0.1.0-beta.147 from npm and update the npm lockfile.
• Remove both obsolete kit tarballs; retain the unrelated patched braces vendor.
• Update current translation docs and the measured bundle sizes. Historical acceptance ledgers remain historical.
• Preserve the plugin-owned backslash adapter: this plugin uses Lingui directly, not createI18nRuntime. No source/API changes, version bump, release, tag or deployment.

Validation

• rpnpm --pull dist --pull coverage run check:ci-workflow: passed all checked-in CI shell steps using real npm ci (strict ten-locale/source checks, contracts, docs, all lint, typecheck, coverage/Jest, integration, exports and production builds).
• Jest: 742 suites / 5657 tests passed (69 suites / 1000 tests skipped, 4 todo by existing configuration). Integration: 5 suites / 77 tests passed, 12 skipped.
• Literal-backslash interpolation regression passed in all ten locales.
• rpnpm --pull dist run check:language-pack-builds: passed both modes and catalogue-graph isolation. Bundled 4,094,305 B; downloadable 3,445,906 B; both below the unchanged strict 5,000,000 B budget.
• npm remains authoritative; local-only pnpm remote-builder bridge files are not committed. Native/mobile tests not rerun for this tooling-only swap.

Merge authorized once hosted CI is green; no check bypasses.