Cloud agents view: Completed group not sorted by completion time (uses createdAt, not firstTerminalAt)

What happened

In the cloud / background agents view (FleetView), the Completed group is not ordered by completion time. The most-recently-completed agent should be at the top, but it isn't.

Reading the relative-time ("time ago") column top-to-bottom in the Completed group, the sequence is neither ascending nor descending:

10h, 4m, 1h, 13m, 4m, 6m, 21m, 1h, 1h, 1d, 27m, 47m, 8m, 23m, 43s, 18m, 18m, 18m, ...

A 43s-ago completion sits below several older 1h/1d items, and a 10h item is pinned at the very top. The long trailing run of identical 18m values points at the actual sort key (see below).

What I expected

The Completed group sorted by completion time, newest first (most-recently-finished agent on top).

Root cause (from inspecting the bundled build)

The Completed group is the done bucket. The default list ordering uses a comparator keyed on creation time, ascending — not completion time:

• Creation-time key: sortOrder ?? Date.parse(createdAt)
• Completion-time key: Date.parse(firstTerminalAt ?? updatedAt) — this exists (firstTerminalAt is stamped once when an agent first reaches a terminal state) but is only applied in the alternate "state" sort mode.

So in the default view the done bucket sorts by createdAt ascending, which is why newest-completed is not on top and why agents sharing a launch batch cluster together (the 18m run). The completion timestamp (firstTerminalAt) is already tracked per agent — the fix is to key the done group's default sort on firstTerminalAt and sort descending.

Environment

• Claude Code: 2.1.202 (also present in 2.1.203/2.1.204)
• Platform: macOS (darwin 25.5.0), arm64

Repro

1. Launch several cloud/background agents at different times so they complete at different times (not in creation order).
2. Open the cloud agents view.
3. Observe the Completed group is ordered by launch/creation time, not by when each agent finished.