feat(ci): build dashboard dev images on VPS (SSD) instead of NAS HDD

Add build-image-dev job (runs-on: vps) - builds with Podman on server2,
pipes the finished image to NAS via SSH, retags from localhost/ prefix.
Deploy job now depends on build-image-dev instead of backend-tests.

NAS HDD I/O was the bottleneck for Docker builds. VPS has SSD and
matches NAS x86_64 architecture perfectly.

.gitea/workflows/deploy-dev.yml

@@ -157,10 +157,37 @@ jobs:
           npm run test:coverage -- --reporter=verbose --run --pool=forks --poolOptions.forks.maxForks=2 || true
           echo "Frontend tests completed (pre-existing Vite compatibility issues may cause failures)"
 
+  build-image-dev:
+    name: Build Dev Image
+    runs-on: vps
+    needs: [backend-tests]
+
+    steps:
+      - name: Checkout repository
+        run: |
+          if [ ! -d .git ]; then
+            git clone --depth=1 "http://100.78.131.124:3300/${GITHUB_REPOSITORY}.git" .
+          fi
+
+      - name: Build dev Docker image
+        run: |
+          set -e
+          echo "Building on VPS (SSD)..."
+          podman build -t nas-dashboard-dev:latest dashboard/
+
+      - name: Transfer image to NAS
+        run: |
+          set -e
+          echo "Streaming dev image to NAS..."
+          podman save nas-dashboard-dev:latest | ssh nasts "/volume1/@appstore/ContainerManager/usr/bin/docker load 2>&1"
+          echo "Retagging image..."
+          ssh nasts "/volume1/@appstore/ContainerManager/usr/bin/docker tag localhost/nas-dashboard-dev:latest nas-dashboard-dev:latest 2>&1 && /volume1/@appstore/ContainerManager/usr/bin/docker image rm localhost/nas-dashboard-dev:latest 2>&1"
+          echo "Dev image transferred and retagged successfully"
+
   deploy-dev:
     name: Deploy to Dev
     runs-on: ubuntu-latest
-    needs: [backend-tests, frontend-tests]
+    needs: [build-image-dev, frontend-tests]
     env:
       SECRET_KEY: test-secret-key-for-ci-environment-32chars-minimum
     container:
@@ -175,42 +202,6 @@ jobs:
             git clone --depth=1 "http://gitea:3000/${GITHUB_REPOSITORY}.git" .
           fi
 
-      - name: Warm mirror cache for base images
-        run: |
-          set -u
-          mirror_host="100.78.131.124:5501"
-
-          prewarm_base_image() {
-            image_ref="$1"
-            if docker image inspect "${image_ref}" >/dev/null 2>&1; then
-              echo "Image ${image_ref} already exists locally, skipping pre-pull"
-              return 0
-            fi
-
-            mirror_ref="${mirror_host}/library/${image_ref}"
-            echo "Attempting mirror pre-pull: ${mirror_ref}"
-            if timeout 30 docker pull "${mirror_ref}" 2>/dev/null; then
-              docker tag "${mirror_ref}" "${image_ref}"
-              echo "Mirror pre-pull succeeded for ${image_ref}"
-            else
-              echo "Mirror pre-pull failed for ${image_ref}, will pull during build"
-            fi
-          }
-
-          prewarm_base_image "node:20-alpine"
-          prewarm_base_image "python:3.12-slim"
-
-      - name: Build dev image
-        run: |
-          set -e
-          export DOCKER_API_VERSION=1.43
-          if ! DOCKER_BUILDKIT=0 docker build --cache-from nas-dashboard-dev:latest -t nas-dashboard-dev:latest dashboard/; then
-            echo "Build failed. Checking for network issues..."
-            curl -I https://registry.npmmirror.com || echo "npmmirror unreachable"
-            curl -I https://pypi.tuna.tsinghua.edu.cn || echo "Tsinghua PyPI unreachable"
-            exit 1
-          fi
-
       - name: Sync runtime compose file
         run: |
           mkdir -p /volume1/docker/nas-dashboard