fix(ci): 预览环境rsync安装兼容Alpine runner（apk替代apt-get）

runtime-builder标签的runner是Alpine系统，没有apt-get，
导致openssh-client和rsync安装失败。改为自动检测包管理器
（apk/apt-get/yum），兼容多种runner环境。

.gitea/workflows/preview-cleanup.yml

@@ -28,7 +28,14 @@ jobs:
       shell: sh
       run: |
         set -eu
-        apt-get update -qq && apt-get install -y -qq openssh-client >/dev/null 2>&1
+        if command -v apk >/dev/null 2>&1; then
+          apk add --no-cache openssh-client >/dev/null 2>&1
+        elif command -v apt-get >/dev/null 2>&1; then
+          apt-get update -qq && apt-get install -y -qq openssh-client >/dev/null 2>&1
+        else
+          echo "ERROR: No package manager found"
+          exit 1
+        fi
         echo "openssh-client installed"
 
     - name: Remove preview directory from server

.gitea/workflows/preview-deploy.yml

@@ -132,11 +132,20 @@ jobs:
             ls -la dist/
           '
 
-    - name: Install SSH client
+    - name: Install SSH client and rsync
       shell: sh
       run: |
         set -eu
-        apt-get update -qq && apt-get install -y -qq openssh-client rsync >/dev/null 2>&1
+        if command -v apk >/dev/null 2>&1; then
+          apk add --no-cache openssh-client rsync >/dev/null 2>&1
+        elif command -v apt-get >/dev/null 2>&1; then
+          apt-get update -qq && apt-get install -y -qq openssh-client rsync >/dev/null 2>&1
+        elif command -v yum >/dev/null 2>&1; then
+          yum install -y openssh-clients rsync >/dev/null 2>&1
+        else
+          echo "ERROR: No package manager found"
+          exit 1
+        fi
         echo "openssh-client and rsync installed"
 
     - name: Deploy preview to server