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/image-generation/technical-design.md

@@ -17,6 +17,14 @@ Main 仅在 `capability === 'image-generation'` 时调用 `withImageConversation
 公开成果事件和消息 metadata 保存，不新增表、迁移、服务端 ID 或 Runtime 会话缓存。
 它是该回复的展示事实，不进入下一轮提示词。
 
+成果页移除后，这条会话图片存储和读取链路继续保留；没有批量迁移或删除 artifact。
+需要项目图片文件时使用 `save_image` 显式保存。其 `artifactId` 是会话图片、上传图片或
+`generate_image` 返回的图片 ID，不依赖成果页；旧消息中的 `artifactIds` 继续有效。
+工具将实际图片文件写入 Runtime 所在主机的绝对路径，远程项目写到远程 Host。
+工作区导入不会创建会话图片记录。工具发现规则见
+[会话图片工具](../conversation-media-generation/technical-design.md#图片保存工具)。
+文件与会话数据的边界见[工作区文件](../assistant-workbar/workspace-files.md#存储与实现)。
+
 ## 上游请求
 
 `ModelAgentRuntime` 将已有文字历史作为会话数据加入提示词，并把本轮要求放在末尾。