Fix Windows build: explicitly install rollup and esbuild native bindings

npm's optional dependency resolution fails to install the Windows
platform-specific native bindings. Install them explicitly.

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

.gitea/workflows/build-app.yml

@@ -123,6 +123,7 @@ jobs:
           if exist node_modules rmdir /s /q node_modules
           if exist package-lock.json del package-lock.json
           npm install
+          npm install @rollup/rollup-win32-x64-msvc @esbuild/win32-x64 --no-save
 
       - name: Build frontend
         working-directory: ./app