[tianxiaochannel-oss88]

Summary

• Hide internal execution scope labels such as read_only and workspace_write from the ordinary conversation timeline.
• Keep the real read/edit/command action rows and their evidence details visible.
• Add regression coverage for hidden scope labels and retained action rows.

Verification

• corepack pnpm --filter @ling-stack/web typecheck
• Targeted Playwright: workflow context inspect details stay out of main feed expansion (1 passed)
• git diff --check

Scope

Only apps/web/src/lib/conversation-work-cell.ts and apps/web/e2e/channel.spec.ts are included.