feat: multilingual glossary templates + inline GlossarySelector rewrite

- Enriched 8 glossary templates with 18,191 translations across 11 languages
  using LLM batch generation + back-translation validation (99.98% confirmed)
- Rewrote GlossarySelector as inline section with template creation
- Fixed sidebar duplicate (single Glossaries link with proOnly flag)
- Added glossaryId reset when sourceLang changes
- Always show GlossarySelector (locked with Pro badge for free users)
- Added source_language flag on glossary cards
- Redirected /dashboard/context to /dashboard/glossaries
- Updated import endpoint to read translations from templates
- Added enrichment script (scripts/enrich_glossary_templates.py)
- Added 6 i18n keys across all 13 locales

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/app/dashboard/translate/useTranslationConfig.ts

@@ -79,6 +79,11 @@ export function useTranslationConfig(hasFile: boolean): UseTranslationConfigRetu
     }
   }, [settings.defaultTargetLanguage]); // eslint-disable-line react-hooks/exhaustive-deps
 
+  // Reset glossary selection when source language changes
+  useEffect(() => {
+    setGlossaryId(null);
+  }, [sourceLang]); // eslint-disable-line react-hooks/exhaustive-deps
+
   // Fetch available (admin-configured) providers
   useEffect(() => {
     const controller = new AbortController();