fix(system-update): 用 compose label 查询容器，修复 isRunning 和自更新助手镜像

- isRunning() 改用 docker ps --filter label=com.docker.compose.service
  兼容 Compose v1 (xuqm_svc_1) 和 v2 (xuqm-svc-1) 命名格式
- 自更新助手镜像改用 getCurrentImage() 从运行中容器的 label 获取，
  不再依赖容器环境变量 REGISTRY/IMAGE_TAG（容器内未注入这两个变量）

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tenant-service/src/main/java/com/xuqm/tenant/service/SystemUpdateService.java

@@ -51,9 +51,14 @@ public class SystemUpdateService {
         // 解决方案：先用 docker run -d 启动一个独立助手容器，它不依附于 tenant-service，
         // 能在 tenant-service 停止后继续完成重建。
         emit.accept(">>> 启动自更新助手容器...");
-        String registry = System.getenv().getOrDefault("REGISTRY", "");
-        String imageTag = System.getenv().getOrDefault("IMAGE_TAG", "latest");
-        String selfImage = registry.isEmpty() ? "alpine" : (registry + "/tenant-service:" + imageTag);
+        // Resolve the image by inspecting the running container via compose labels,
+        // so we don't depend on REGISTRY/IMAGE_TAG being present in the container env.
+        String selfImage = getCurrentImage();
+        if (selfImage == null) {
+            emit.accept(">>> [错误] 无法获取当前 tenant-service 镜像名，请检查容器标签或手动执行更新。");
+            emit.accept("DONE");
+            return;
+        }
         boolean helperStarted = spawnSelfUpdater(composeFile, selfImage);
 
         if (helperStarted) {
@@ -100,19 +105,39 @@ public class SystemUpdateService {
         }
     }
 
+    // Use compose labels instead of container name — works with both Compose v1 (xuqm_svc_1)
+    // and Compose v2 (xuqm-svc-1) naming conventions.
     private boolean isRunning(String service) {
-        String containerName = "xuqm-" + service;
         try {
-            Process p = new ProcessBuilder("docker", "inspect", "--type=container", containerName)
-                    .redirectErrorStream(true)
-                    .start();
-            p.getInputStream().transferTo(java.io.OutputStream.nullOutputStream());
-            return p.waitFor() == 0;
+            Process p = new ProcessBuilder(
+                    "docker", "ps", "-q",
+                    "--filter", "label=com.docker.compose.project=xuqm",
+                    "--filter", "label=com.docker.compose.service=" + service
+            ).redirectErrorStream(true).start();
+            String out = new String(p.getInputStream().readAllBytes()).trim();
+            p.waitFor();
+            return !out.isEmpty();
         } catch (Exception e) {
             return false;
         }
     }
 
+    private String getCurrentImage() {
+        try {
+            Process p = new ProcessBuilder(
+                    "docker", "ps",
+                    "--filter", "label=com.docker.compose.project=xuqm",
+                    "--filter", "label=com.docker.compose.service=tenant-service",
+                    "--format", "{{.Image}}"
+            ).redirectErrorStream(true).start();
+            String out = new String(p.getInputStream().readAllBytes()).trim();
+            p.waitFor();
+            return out.isEmpty() ? null : out;
+        } catch (Exception e) {
+            return null;
+        }
+    }
+
     private void exec(Consumer<String> emit, String... cmd) {
         try {
             Process p = new ProcessBuilder(cmd)