ci: make docker registry and compose steps idempotent on self-hosted runners (#12012)

The registry container is started with --restart=always but never
removed during teardown, so once a machine runs the job, every later
run on that machine fails with a container name conflict. Reuse the
running container when it exists and recreate it only when missing or
broken.

Some self-hosted runners (e.g. seaweedfs-server03) also lack the
Docker Compose plugin, so install it via docker/setup-compose-action,
which is a no-op where compose is already available.

.github/workflows/pjdfstest.yml

@@ -41,13 +41,20 @@ jobs:
         cache: ${{ runner.environment == 'github-hosted' }}
 
     - name: Start local Docker registry
-      run: docker run -d --restart=always -p 5000:5000 --name registry registry:2
+      run: |
+        if ! docker start registry 2>/dev/null; then
+          docker rm -f registry >/dev/null 2>&1 || true
+          docker run -d --restart=always -p 5000:5000 --name registry registry:2
+        fi
 
     - name: Set up Docker Buildx
       uses: docker/setup-buildx-action@v4
       with:
         driver-opts: network=host
 
+    - name: Set up Docker Compose
+      uses: docker/setup-compose-action@v2
+
     - name: Build weed race binary
       run: |
         cd docker

.github/workflows/samba-integration.yml

@@ -43,13 +43,20 @@ jobs:
         cache: ${{ runner.environment == 'github-hosted' }}
 
     - name: Start local Docker registry
-      run: docker run -d --restart=always -p 5000:5000 --name registry registry:2
+      run: |
+        if ! docker start registry 2>/dev/null; then
+          docker rm -f registry >/dev/null 2>&1 || true
+          docker run -d --restart=always -p 5000:5000 --name registry registry:2
+        fi
 
     - name: Set up Docker Buildx
       uses: docker/setup-buildx-action@v4
       with:
         driver-opts: network=host
 
+    - name: Set up Docker Compose
+      uses: docker/setup-compose-action@v2
+
     - name: Build weed race binary
       run: |
         cd docker