feat(i18n): add full-stack internationalization support

Add languages and entity_translations tables to database schema
Implement localized queries and translation management in backend
Integrate frontend i18n and add translation UI components

frontend/package.json

@@ -12,9 +12,11 @@
     "test": "vitest run"
   },
   "dependencies": {
+    "@iconify/vue": "^5.0.0",
     "@vitejs/plugin-vue": "latest",
     "vite": "latest",
     "vue": "latest",
+    "vue-i18n": "^11.4.0",
     "vue-router": "latest"
   },
   "devDependencies": {