ci(i18n): fail on new English-identical translations

The drift check only warned about locale values identical to English, so
untranslated strings kept landing. It now fails on any such value that
tools/i18n/identical-en-baseline.json does not record for that locale and
key. The baseline captures today's 2,015 entries: legitimately identical
values (brand and technical names, language autonyms, PIN) and the
existing debt. An entry only covers the English text it recorded, so
copying reworded English into a locale fails too.

Baseline entries that are no longer identical are reported, not fatal.
`pnpm run i18n:baseline:update` rewrites the baseline deliberately; CI
runs `pnpm run i18n:validate` (node tests, then the check) and never
rewrites it. `--fail-on-identical` remains as a strict audit.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -390,8 +390,12 @@ jobs:
             - name: Typecheck Jest spec programs
               run: pnpm run typecheck:spec:test && pnpm run typecheck:spec
 
-            - name: Check i18n drift
-              run: pnpm run i18n:check
+            # Fails on missing or extra keys and on values identical to
+            # English that tools/i18n/identical-en-baseline.json does not list.
+            # The baseline only changes through a reviewed
+            # `pnpm run i18n:baseline:update`; CI never rewrites it.
+            - name: Check i18n drift and untranslated values
+              run: pnpm run i18n:validate
 
             # Node specs for the benchmark and journey harness (about ten
             # seconds). They live in the E2E app, which the unit coverage scope