feat(i18n): add Russian (ru) locale

Full Russian catalog (11,154 keys, 1:1 with en, identical nesting) and every
locale wiring point the app declares, so ru is a first-class locale instead
of an English fallback:

- messages/ru.json, project.inlang/settings.json, i18n boot script
- i18n config / load-locale, format-locale (ru-RU), date-fns ru
- labs: parse-reference-range RANGE_PROSE for Russian lab sheets
  ("3,5 - 5,0", "от 3,5 до 5,0", "до 5,6", "не более 5,6")
- AI: citation-coverage normative stems, coach system prompt and insights
  reply footer (Russian prompts must override the hard-coded
  "Respond in English"), population-norm patterns
- safety: outbound-screen Russian imperative/dose/unit/causality bank
- mental health: PHQ-9, GAD-7, WHO-5 and SCI wording

verify-message-catalogs.mjs passes for all 10 locales.

scripts/generate-i18n-boot.mjs

@@ -28,7 +28,7 @@ const __dirname = dirname(fileURLToPath(import.meta.url));
 const repoRoot = join(__dirname, "..");
 const outDir = join(repoRoot, "public", "i18n");
 
-const LOCALES = ["de", "en", "fr", "es", "it", "pl", "ko", "nl", "pt-BR"];
+const LOCALES = ["de", "en", "fr", "es", "it", "pl", "ko", "nl", "pt-BR", "ru"];
 
 mkdirSync(outDir, { recursive: true });