ci: use rust runner native environment (no container override)

The rust runner pod is pre-configured with:
- Rust 1.83-bookworm base image
- Docker CLI + Node.js (for GitHub Actions)
- Git + all build tools
- TLS-secured docker daemon connection at tcp://localhost:2376

Don't override with a container image. Use the runner's native environment.
This is the correct pattern for self-hosted runners.

.gitea/workflows/build.yaml

@@ -9,50 +9,41 @@ jobs:
   build-and-push:
     name: Build and Push Image
     runs-on: rust
-    container:
-      image: docker:27-dind
-      options: --privileged
-    env:
-      REGISTRY: forgejo.riotpiao.com
-      IMAGE: forgejo.riotpiao.com/rock/poimen-memory
+    # NO container specified - use runner's native environment
+    # The rust runner has: Rust 1.83-bookworm + docker CLI + git
+    # Docker daemon available at: tcp://localhost:2376 (TLS)
     steps:
       - name: Checkout code
-        run: |
-          apk add --no-cache git
-          git clone https://git.riotpiao.com:2222/rock/poimen-memory.git /src
-          cd /src
-          git checkout ${{ github.sha }}
+        uses: actions/checkout@v4
 
       - name: Get commit info
         id: info
         run: |
-          cd /src
           SHORT_SHA=$(git rev-parse --short HEAD)
           echo "short_sha=${SHORT_SHA}" >> $GITHUB_OUTPUT
-          echo "Commit SHA: ${SHORT_SHA}"
+          echo "Building: ${SHORT_SHA}"
 
       - name: Docker login
         run: |
           echo "${{ secrets.REGISTRY_PAT }}" | \
-          docker login -u rock --password-stdin ${{ env.REGISTRY }}
+          docker login -u rock --password-stdin forgejo.riotpiao.com
 
       - name: Build image
         run: |
-          cd /src
           docker build \
-            --tag ${{ env.IMAGE }}:${{ steps.info.outputs.short_sha }} \
-            --tag ${{ env.IMAGE }}:latest \
+            --tag forgejo.riotpiao.com/rock/poimen-memory:${{ steps.info.outputs.short_sha }} \
+            --tag forgejo.riotpiao.com/rock/poimen-memory:latest \
             .
           echo "✅ Image built successfully"
 
       - name: Push image
         run: |
-          docker push ${{ env.IMAGE }}:${{ steps.info.outputs.short_sha }}
-          docker push ${{ env.IMAGE }}:latest
+          docker push forgejo.riotpiao.com/rock/poimen-memory:${{ steps.info.outputs.short_sha }}
+          docker push forgejo.riotpiao.com/rock/poimen-memory:latest
           echo "✅ Image pushed successfully"
 
       - name: Cleanup
         if: always()
         run: |
-          docker logout ${{ env.REGISTRY }} || true
+          docker logout forgejo.riotpiao.com || true
           echo "✅ Cleanup complete"