Browser check: the focused-window reclaim check waits for a resize the first attach no longer sends #2294

The browser lane's scripts/ui-contexts-regression.ts fails twice in a row at scripts/chat-size-regression.ts:1203 (checkFocusedWindowReclaimsTerminalSize, called from :1209):

TimeoutError: waitForFunction: Timeout 10000ms exceeded.
  at scripts/chat-size-regression.ts:1203:18
  at checkFocusedWindowReclaimsTerminalSize (scripts/chat-size-regression.ts:1209:31)

Seen on CI runs 40747942163 (attempt 2), 40752979716 (attempt 2, #2290 @49a7457c), 40775590966 (attempt 2) and 40775945562 (attempt 2, #2293 @d619ea0f). None of these PRs touch terminal attach or resize. A scan of every ui-regression job since 2026-10-27 12:00Z finds the first one at 2026-10-28 18:46Z, after #2272 and #2255 merged.

The check waits for an outgoing resize frame after the desktop window's attach. Since #2272 a new terminal attaches only once its first font is set, so the attach already carries the final grid and often no resize follows it. Locally the page sent only attach 121x41 (no keep_size) and the pane's shell reported stty size = 41 121: the pty has the right size, and the check waits for a frame the product no longer needs to send. Reproduced 4/4 with CHAT_SIZE_CASE=reclaim bun scripts/chat-size-regression.ts.