flake: G1.44 'open tabs come back after a socket replaced before the first ready' misses Starting… on CI #513

Found while working #496 (pin PR #504, CI run 38846029191, e2e shard 1/3). Green on rerun.

What failed

test/e2e/g1-startup.spec.js:110, at line 129: expect(starting(page)).toBeVisible() right after replaceSocket(page) — element not found.

Reproduction attempts

• The PR head locally: 96/96 green (--repeat-each 8, 4 workers, twice).
• main (54b221a) under full CPU load: 20/20 green.

Likely cause (reasoned, not shown)

replaceSocket fast-forwards the page clock 31 s at a time, up to 7 steps, until the browser opens a new socket. On a slow runner the new socket can open several steps late, so the clock passes the two-minute mark and the banner has already moved from "Starting…" to "eve isn't responding." (G1.44.r1) when line 129 looks. The fix would be the smallest change that makes the step count deterministic, e.g. stop fast-forwarding once the heartbeat has fired once and wait on the websocket event alone.