feat: PKCE auth + CI/CD deploy

- Frontend: PKCE flow (oauth.ts, AuthCallback code exchange, 401 interceptor)
- Backend: token introspection via SuperOAuth (no more JWT secret)
- User model: superOauthId (unified) replaces oauthId+provider
- Cookies httpOnly session + refresh token
- POST /auth/refresh endpoint
- Gitea CI workflow (vps-runner pattern)
- DB_SYNC env var for initial schema creation

frontend/package.json

@@ -0,0 +1,36 @@
+{
+  "name": "frontend",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc -b && vite build",
+    "lint": "eslint .",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "@tanstack/react-query": "^5.90.21",
+    "lucide-react": "^0.577.0",
+    "react": "^19.2.4",
+    "react-dom": "^19.2.4",
+    "react-router-dom": "^7.13.1"
+  },
+  "devDependencies": {
+    "@eslint/js": "^9.39.4",
+    "@types/node": "^24.12.0",
+    "@types/react": "^19.2.14",
+    "@types/react-dom": "^19.2.3",
+    "@vitejs/plugin-react": "^6.0.0",
+    "autoprefixer": "^10.4.27",
+    "eslint": "^9.39.4",
+    "eslint-plugin-react-hooks": "^7.0.1",
+    "eslint-plugin-react-refresh": "^0.5.2",
+    "globals": "^17.4.0",
+    "postcss": "^8.5.8",
+    "tailwindcss": "^4.2.1",
+    "typescript": "~5.9.3",
+    "typescript-eslint": "^8.56.1",
+    "vite": "^8.0.0"
+  }
+}