fix(agent-pane): align running tray trailing columns

Merged
TE
7d ago
+294-19

Depends on #27103

Leo: "the ALIGNMENT ON THIS IS WEIRD AS FUCK"

The expanded running tray now uses shared fixed trailing tracks for time, status plus chevron, and stop. Rows retain empty time and stop slots so Running › and the header's time and chevron stay aligned across running subagents, commands, and started chats. The stop control remains outside the row button. Width and side insets remain owned by #26637.

Gallery stills (expanded between-turns tray, with rows that have and lack time and stop controls):

Tray columns dark
Tray columns light

Gallery advisory state: agent-pane.subagent-tray?variant=between-turns.

Tests:

  • bun run check (Node 24)
  • bun test test/subagent-tray.test.tsx test/subagent-tray-layout.test.ts test/subagent-tray-motion.test.tsx
  • CMUX_BROWSER_TESTS=1 bun test test/subagent-tray-columns.test.ts test/running-strip.test.ts

Risk: normal.

Agent session: agent session