ci: 修复 Rust lint job 构建错误

在 Rust lint job 中添加前端构建步骤，确保 dist 目录存在。
这样 Tauri 的 generate_context! 宏才能正常工作。

修复错误：
- The `frontendDist` configuration is set to `"../dist"` but this path doesn't exist

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

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

.github/workflows/ci.yml

@@ -13,11 +13,17 @@ jobs:
   lint:
     name: Lint & Format
     runs-on: ubuntu-latest
-    
+
     steps:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
       - name: Setup Rust
         uses: dtolnay/rust-toolchain@stable
         with:
@@ -34,6 +40,12 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y libwebkit2gtk-4.1-dev libappindicator3-dev librsvg2-dev patchelf libssl-dev
 
+      - name: Install frontend dependencies
+        run: npm ci
+
+      - name: Build frontend
+        run: npm run build
+
       - name: Check formatting
         working-directory: src-tauri
         run: cargo fmt --all -- --check