fix(client): intercept the alpha chat file-open funnel (remote.session.openWorkspacePath)

0.1.2-alpha 宿主删除了 ctx.workspaces.openPath，聊天文件点击全部改走
remote 命名空间，旧拦截成为死代码（点击穿透到 xdg-open）。改为在
ctx.inject(['remote.session']) 内以 defineProperty 遮蔽该方法（accessor
属性，赋值无效），接管时返回 RemoteResult 成功包络。语义不变，

设计：docs/plans/2026-08-31-openpath-intercept-alpha-design.md

src/prefs-shared.ts

@@ -63,9 +63,9 @@ export interface SidebarPrefs {
   /**
    * Whether chat-side file opens (tool-row path links, the produced-files
    * row, prose file mentions — every path that funnels through the client
-   * runtime's `ctx.workspaces.openPath`) open in the sidebar editor instead
-   * of the Host OS's default application. On by default; the editor tab's
-   * own enable switch gates it too (both must be on for the takeover).
+   * runtime's `remote.session.openWorkspacePath`) open in the sidebar editor
+   * instead of the Host OS's default application. On by default; the editor
+   * tab's own enable switch gates it too (both must be on for the takeover).
    */
   interceptOpenPath: boolean
   /**