docs(changelog): correct the failure mode — English fallback, not blank text

An absent key is not rendered blank: deepMergeFallback in src/i18n/request.ts
substitutes the English value when targetValue === undefined, so the nine EU
locales showed the compare panel untranslated rather than empty. The fix is
unchanged; the description of what users saw was wrong.

changelog.d/fixes/orchestration-fase3-eu-locales.md

@@ -1,7 +1,9 @@
 - **fix(i18n):** the nine locales added with the EU-language batch (Greek, Estonian, Irish,
   Croatian, Lithuanian, Latvian, Maltese, Slovenian, Serbian) were missing the eleven
   Orchestration Canvas keys that Phase 3 introduced, so the compare-runs panel and the
-  "no runs match these filters" empty state had no text in those languages. The coverage gate
-  did not catch it: it enforces an 80% floor per locale, and nine missing keys out of ~13,000
-  never approaches that. Translated for real in each language, calibrated against the wording
-  each file already uses for "run", "filter" and "skill".
+  "no runs match these filters" empty state fell back to English in those languages
+  (`deepMergeFallback` substitutes English for an absent key, so nothing rendered blank —
+  it rendered untranslated). The coverage gate does not catch this: it enforces an 80% floor
+  per locale, and eleven missing keys out of ~13,000 leaves coverage at 99.9%. Translated for
+  real in each language, calibrated against the wording each file already uses for "run",
+  "filter" and "skill".