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/deepseek-harness/README.md

@@ -18,7 +18,7 @@
 未发布实现的验收状态见[工作栏进度](../assistant-workbar/progress.md#2026-09-14-runtime-进程复用实施中)。
 
 The separate official Web client is pinned to `@deepseek-ai/dsh@0.1.7-rc.2`.
-Its Main service API, Ask/Execute policy, capability adapters, packaged resource
+Its Main service API, unified execution rules, capability adapters, packaged resource
 layout, and Windows validation are documented in
 [Native Client Proposal, section 9.1](../assistant-workbar/runtime-native-client-proposal.md#91-ds-web-backend-2026-09-26).
 This Web resource tree is prepared separately from the background Harness Host.