feat: update extractor for all 5 languages, update import for multi-language

- Extract.ts now processes all 5 language files, filters non-English
  entries by lang_code, skips translation extraction for non-English
  (no translations in source files)
- Import.ts now imports all 5 language output files, uses language
  field from ExtractedSense instead of hardcoding en
- Sample limit hardcoded to 500 entries per language for development

data-pipeline/package.json

@@ -4,6 +4,7 @@
   "private": true,
   "type": "module",
   "scripts": {
+    "extract": "tsx stage-1-extract/scripts/extract.ts",
     "db:import": "tsx db/import.ts",
     "db:init": "tsx db/init.ts",
     "annotate": "tsx stage-2-annotate/scripts/annotate.ts",