fix: Add missing frontend dependencies (pinia, vue-router, lucide-vue-next)

These were installed in the previous session but not saved to package.json.
Production build now succeeds (39KB gzipped).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/package.json

@@ -9,8 +9,11 @@
     "preview": "vite preview"
   },
   "dependencies": {
+    "lucide-vue-next": "^0.564.0",
+    "pinia": "^3.0.4",
     "pinia-plugin-persistedstate": "^4.7.1",
-    "vue": "^3.5.25"
+    "vue": "^3.5.25",
+    "vue-router": "^5.0.2"
   },
   "devDependencies": {
     "@tailwindcss/vite": "^4.1.18",