#33364 Running tray: the open list is newest first, the folded bar names the newest one

Leo, 2026-11-03: "ok this previews one of the latest but it doesn't show in latest it shows in oldest order"

His nightly showed the folded running bar naming the newest items ("Context around the ask and memory search · glaeda-gh wait … +6 more"), while the open list showed the oldest at the top (the 15m 45s command first, the newest at the bottom).

• Open list, newest first. trayItems (subagents/runningTray.ts) now orders what runs newest first, the same order the folded bar names, so the top row is what just started. A nested subagent stays under its parent, and the subtree moves with the parent's start time. Items with no start time (started chats) go last, in their list order. Finished cards are unchanged; they were already ordered by most recent end.
• Folded bar, one name. trayFoldHead.experiment.ts's default arm is now one: one newest name that fits instead of two that are both cut, as in his screenshot. The two and counts arms remain in the gallery (agent-pane.subagent-tray-names).

Design spec: design/running-tray.md (the folded header names what runs).

Tests: test/subagent-tray-names.test.tsx (a new order test, plus the folded bar's one name and +N), and subagent-tray.test.tsx and agent-pane-subagents-fixture.test.ts updated for the new order. Locally, test/agent-pane-workflow-progress.test.tsx fails 2 tests ("1 failed") with or without this change.

Agent session: agent session

🤖 Generated with Claude Code

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Summary by cubic

Fixes the running subagents tray from showing the oldest item at the top of the open list when the folded bar named the newest one, so both views now agree.

• The open list orders running items newest first; nested subagents stay under their parent, and parent subtrees move by the parent's start time.
• Started chats without a start time go last, in their existing list order.
• The folded bar's default now shows one newest name that fits instead of two cut-off ones; the two and counts alternatives remain available behind the experiment.
• Finished cards are unchanged; they already listed most recently ended first.