feat: unify execution and add workspace file imports

Remove Ask/Execute modes and general product tool approvals so requests use the selected runtime, enabled capabilities, and execution account permissions. Migrate retired application metadata while preserving user content.

Retire the Results page while retaining conversation images and stored artifacts. Add local and remote workspace file imports, timestamps and sorting, improve image discovery and saving, and refine workspace navigation and supervision responsiveness. Include the accompanying web-search changes, tests, probes, and product documentation.

Remote imports require an updated Agent. Existing artifacts are not automatically copied into project directories. Validation evidence and outstanding failures remain documented in feature progress files; no full test suite or real-model calls were rerun for this commit.

Release note: Run requests without switching work modes, import files into a selected local or remote workspace folder, sort workspace files by date, and keep using conversation images after removal of the Results page.

docs/features/device-sharing/prd.md

@@ -170,7 +170,7 @@ GoodBuddy 的能力当前主要在本机执行，SSH 远程项目则要求用户
 
 ### FR-14 与现有能力的边界
 
-- 远端调用不能扩大 Ask/Execute、Workspace、MCP、Skill 和知识库现有权限。
+- 远端调用不能扩大 Workspace、MCP、Skill 和知识库既有能力范围，沿用统一执行规则。
 - 本机提供任务时使用能力声明对应的 Runtime 边界。
 - SSH 远程项目、本机工具环境和模型配置默认不向 Peer 或网关传播。