[cherry-pick] [cherry-pick] agentHost: Preserve workspace transition boundaries - #334793

Cherry-pick of #334694 from release/1.137.

⚠️ This cherry-pick has merge conflicts that need manual resolution. Conflict markers (<<<<<<</=======/>>>>>>>) are committed to the branch — check it out locally, resolve, and force-push.

git fetch origin cherry-pick/334694 && git checkout cherry-pick/334694
# resolve conflicts, then:
git add -A && git commit --amend --no-edit && git push --force-with-lease

Conflicting files:

• src/vs/workbench/contrib/chat/test/browser/widget/chatListRenderer.test.ts

Summary

Backport of #334534 to release/1.137.

• skip workspace trust prompts when effective permissions are Allow All or global auto-approve is enabled
• preserve the always-visible Now working in workspace transition boundary across collapsed progress and Agent Host restarts
• hide the internal continuation request while preserving provider output and file-change attribution
• persist transition state atomically and serialize transition restoration with turn-ID mapping writes
• expose truncated transition labels through the standard hover service

This branch contains only the five commits from #334534. The prerequisite workspace-conversion implementation from #334250 is already present on release/1.137.

Validation

• npm run typecheck-client
• targeted ESLint across all 26 changed TypeScript files
• targeted Stylelint for the transition CSS
• npm run transpile-client
• 848 focused unit tests passed, 38 pending
• git diff --check