fix(i18n): re-translate Italian locale (was ~51% Spanish) + contamination guard

.github/workflows/ci.yml

@@ -46,6 +46,9 @@ jobs:
       - name: Check i18n key coverage
         run: node scripts/check-i18n-keys.js
 
+      - name: Check locale cross-contamination (wrong-language values)
+        run: node scripts/check-locale-contamination.js
+
       - name: Check dictionary coverage (POSITIONING.md "48h" SLA)
         run: node scripts/check-dict-coverage.js
 

CHANGELOG.md

@@ -6,6 +6,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 ## [Unreleased]
 
+### Fixed
+- **Italian locale was ~51% Spanish.** `src/data/it.json` had been built from `es.json` and only partially re-translated — 632 of its long strings were byte-identical Spanish, and the `_protected` brand map mistranslated `Claude → Claudio`, `Anthropic → Antropico`, `Claude Code → Codice Claudio`, silently breaking runtime brand-term restoration for Italian (our #1 install market). Re-translated every contaminated string from the English source via the same Google Translate endpoint the extension uses, restored brand/technical terms to canonical English, and rebuilt `_protected` with the correct Italian wrong-forms. Italian↔Spanish overlap is now 0.1% (parity with the other 10 locales).
+
+### Added
+- **Locale cross-contamination guard** (`scripts/check-locale-contamination.js`, `npm run check:locales`, wired into CI). Fails when any locale shares >8% of its long strings with another — the bug class the key/shape checks (`check-i18n`, `check-dict-coverage`) cannot see because they only verify structure, not language. Clean locales sit at ≤2.1%; the contaminated Italian file was 51%.
+
 ## [3.5.39] - 2026-06-01
 
 ### Security

package.json

@@ -17,6 +17,7 @@
     "check:dicts": "node scripts/check-dicts.js",
     "check:sync": "node scripts/check-bg-sync.js",
     "check:i18n": "node scripts/check-i18n-keys.js",
+    "check:locales": "node scripts/check-locale-contamination.js",
     "check:dict-coverage": "node scripts/check-dict-coverage.js",
     "check:academy": "node scripts/check-academy-courses.js",
     "check:cws-drift": "node scripts/check-cws-drift.js",