✨ feat(vscode): PyCharm 启动命令可配置（支持 ~/绝对路径），抽 expandTilde 复用

GUI 启动的 VS Code 扩展进程 PATH 常不含 JetBrains 启动器，裸 pycharm 易 ENOENT。
新增设置 pycharmCommand（默认 pycharm），贯穿 store/settings handler/messages/
KanbanPanel 与 webview，「钩子」分组在选 PyCharm 时显示「PyCharm 启动命令」输入框。
handleOpenWorktree 用该命令并经 expandTilde 展开 ~。expandTilde 从 resolveWorktreePath
抽出共用。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

vscode/src/panel/messages.ts

@@ -63,6 +63,7 @@ export type ExtensionToWebview
       autoBuildBranch: string
       worktreeDirectory: string
       worktreeOpenWith: 'vscode' | 'pycharm'
+      pycharmCommand: string
       worktreePostCreateScript: string
       worktreePreRemoveScript: string
       implTabPreCreateScript: string
@@ -119,6 +120,7 @@ export type WebviewToExtension
       autoBuildBranch: string
       worktreeDirectory: string
       worktreeOpenWith: 'vscode' | 'pycharm'
+      pycharmCommand: string
       worktreePostCreateScript: string
       worktreePreRemoveScript: string
       implTabPreCreateScript: string