Update CI workflow by adding frontend asset upload and download steps

.gitea/workflows/ci.yml

@@ -23,12 +23,23 @@ jobs:
         run: bash scripts/check.sh
       - name: Build frontend
         run: bash scripts/build.sh
+      - name: Upload frontend assets
+        uses: actions/upload-artifact@ff15f0306b3f739f7b6fd43fb5d26cd321bd4de5 # v3
+        with:
+          name: frontend-build
+          path: build/
 
   build-backend:
     runs-on: ubuntu-latest
+    needs: build-frontend
     steps:
       - name: Checkout
         uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - name: Download frontend assets
+        uses: actions/download-artifact@9bc31d5ccc31df68ecc42ccf4149144866c47d8a # v3
+        with:
+          name: frontend-build
+          path: build/
       - name: Setup Go
         uses: actions/setup-go@40f1582b2485089dde7abd97c1529aa768e1baff # v5
         with: