fix(review): correct the i18n coverage claim to measured reality

The refresh claimed "Full translation coverage across all non-English
locales (no English fallback strings)", but measuring i18n.js directly
falsifies it: full-sentence keys are English-identical in several locales
(e.g. gateway_start_success: 'Gateway start completed.' appears verbatim in
4+ locale blocks) -- ~30/1574 keys for Czech (~2%), 66 for Polish, 140 for
Vietnamese, 243 for Turkish (~15%). These are genuine untranslated
fallbacks on recently added keys, consistent with the repo's documented
add-keys-with-English-fallback convention.

Reword the line to the accurate shape (near-full coverage, measured
fallback tail, backfilled by periodic translation passes) so the accuracy
refresh stays accurate.

ROADMAP.md

@@ -262,7 +262,7 @@ work has shifted from "reach parity" to "harden reliability + widen distribution
 
 ### Internationalization
 - [x] 15 locales — English, Italian, Japanese, Russian, Spanish, German, Chinese (zh + zh-Hant), Portuguese, Korean, French, Czech, Turkish, Polish, Vietnamese
-- [x] Full translation coverage across all non-English locales (no English fallback strings)
+- [x] Near-full translation coverage across non-English locales — a small English-fallback tail remains on recently added keys (measured ~2% for Czech up to ~15% for Turkish), backfilled by periodic translation passes
 - [x] Key-parity test ensures every locale has every key
 - [x] Right-to-left and CJK input (IME composition fixes)