Add Gitea runner build workflow

.gitea/workflows/build.yml

@@ -0,0 +1,38 @@
+name: Build
+
+on:
+  push:
+    branches:
+      - master
+      - main
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "24"
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run tests
+        run: npm test
+
+      - name: Build web artifact
+        run: npm run build
+
+      - name: Upload dist artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: league-of-legends-gui-overhaul-dist
+          path: dist/
+          if-no-files-found: error