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/smart-heartbeat/prd.md

@@ -62,7 +62,7 @@
 - 不修改 Task、Job 或 Task Center 模型。
 - 不新增独立 Automation Center。
 - 不移除定时任务现有入口。
-- 不扩大智能心跳的工具、目录、网络或 Execute 权限。
+- 不扩大智能心跳的工具、目录或网络权限，内部文本分析保持无工具。
 - 不让智能心跳跨越配置范围读取数据。
 - 不将现有心跳建议静默转换成 Task。