fix(plugin): close cancellable install lifecycle gaps

app/adapters/system/host.py

@@ -188,9 +188,11 @@ class SystemUtils:
             grace_seconds: float = 5,
     ) -> None:
         """终止安装子进程及其同组子进程，并确保句柄已回收。"""
+        process_tree = SystemUtils._process_tree(process.pid)
         if process.returncode is None:
             try:
                 if os.name == "nt":
+                    SystemUtils._signal_process_tree(process_tree)
                     process.terminate()
                 else:
                     os.killpg(process.pid, signal.SIGTERM)
@@ -205,9 +207,11 @@ class SystemUtils:
         except (asyncio.TimeoutError, asyncio.CancelledError):
             try:
                 if os.name == "nt":
+                    SystemUtils._signal_process_tree(process_tree, force=True)
                     process.kill()
                 else:
                     os.killpg(process.pid, signal.SIGKILL)
+                    SystemUtils._signal_process_tree(process_tree, force=True)
             except (ProcessLookupError, OSError):
                 pass
             try:
@@ -224,6 +228,27 @@ class SystemUtils:
             except (ProcessLookupError, OSError):
                 pass
 
+    @staticmethod
+    def _process_tree(pid: int) -> list[psutil.Process]:
+        """收集安装进程及其后代，避免构建进程继续写运行环境。"""
+        try:
+            parent = psutil.Process(pid)
+            return [parent, *parent.children(recursive=True)]
+        except (psutil.Error, OSError):
+            return []
+
+    @staticmethod
+    def _signal_process_tree(
+            processes: list[psutil.Process],
+            force: bool = False,
+    ) -> None:
+        """向进程树发送终止或强制结束信号。"""
+        for child in reversed(processes):
+            try:
+                (child.kill if force else child.terminate)()
+            except (psutil.Error, OSError):
+                continue
+
     @staticmethod
     async def execute_with_subprocess_async(
             command: list,

app/adapters/system/plugin/package.py

@@ -101,16 +101,18 @@ class PluginPackageManager:
     @staticmethod
     def rollback(checkpoint: PluginPackageCheckpoint) -> None:
         """删除当前包并把变更前文件快照恢复到运行目录。"""
-        if checkpoint.plugin_dir.exists():
-            shutil.rmtree(checkpoint.plugin_dir)
         snapshot_dir = checkpoint.transaction_dir / "package"
         if checkpoint.existed:
             if not snapshot_dir.is_dir():
                 raise FileNotFoundError(
                     f"插件 {checkpoint.plugin_id} 的补偿快照不存在：{snapshot_dir}"
                 )
+        if checkpoint.plugin_dir.exists():
+            shutil.rmtree(checkpoint.plugin_dir)
+        if checkpoint.existed:
             shutil.copytree(snapshot_dir, checkpoint.plugin_dir)
-        shutil.rmtree(checkpoint.transaction_dir, ignore_errors=False)
+        if checkpoint.transaction_dir.exists():
+            shutil.rmtree(checkpoint.transaction_dir, ignore_errors=False)
 
     async def async_rollback(self, checkpoint: PluginPackageCheckpoint) -> None:
         """在线程池中恢复插件包文件快照。"""