Stabilise first app launch in mobile e2e on CI #62

The mobile e2e job passed on #60, but the first active workout test failed its initial launch and passed on retry.

The failure occurred before the workout flow, in resetAndLaunch at e2e/tests/helpers.ts:60.

start workout, log a set, rest timer appears
Error: app did not come to foreground
at resetAndLaunch (e2e/tests/helpers.ts:60:13)
retry #1 passed
1 flaky
3 passed (6.2m)

Evidence is in the CI job log and e2e report artifact.

Investigate first-launch readiness on the fresh CI simulator and make the launch helper reliable without hiding real startup failures. Verify the active workout flow on a fresh simulator and retain launch failure diagnostics. The release configuration slice changed no app or e2e code.