Add 'Seed Defaults' button to load all predefined translations

- Add /translations/seed-all-defaults API endpoint
- Loads all DEFAULT_TRANSLATIONS (makers, models, colors, fuels, transmissions)
- Includes 100+ predefined translations (Mohave, Sonata, colors, etc.)
- Add 'Seed Defaults' button to admin translations page

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/lib/api.ts

@@ -294,6 +294,11 @@ export const translationsApi = {
     return data;
   },
 
+  seedAllDefaults: async (): Promise<{ message: string; added: number; skipped: number; categories: string[] }> => {
+    const { data } = await api.post('/translations/seed-all-defaults');
+    return data;
+  },
+
   bulkLookup: async (texts: string[], lang: string, category?: string): Promise<{ translations: Record<string, string> }> => {
     const { data } = await api.post('/translations/bulk-lookup', {
       texts,