feat(gha): build base theme

WEB-4112

.github/workflows/build.yml

@@ -0,0 +1,36 @@
+name: Build
+on:
+  workflow_dispatch:
+
+jobs:
+  install-deps:
+    runs-on:
+      group: self-hosted
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - uses: pnpm/action-setup@v4
+        name: Install pnpm
+        with:
+          version: 8
+      - name: Install Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+      - name: Install dev dependencies
+        run: |
+          pnpm install
+      - name: Build theme
+        run: |
+          pnpm --theme=base build
+      - name: Archive theme
+        uses: actions/[email protected]
+        with:
+          name: basetheme
+          path: |
+            base/
+