🐛 fix(vscode): issue/patch 用 null 清空 worktree 字段以便 webview 即时刷新

vscode/src/panel/handlers/worktree.ts

@@ -144,12 +144,13 @@ export async function handleDeleteWorktree(panel: KanbanWebviewPanel, issueNumbe
     token,
   })
 
+  // null 才能过 postMessage 序列化；undefined 会被丢掉，webview 合并不清字段
   panel.postMessage({
     type: 'issue/patch',
     issueNumber,
     patch: {
-      worktreePath: undefined,
-      branch: undefined,
+      worktreePath: null,
+      branch: null,
       worktreeExists: false,
     },
   })