Fix the confusing flow: tapping Share Screen dumped the user straight into a
meeting and auto-shared, with the join code hard to find. Now it shows a clear
full-screen "Share your screen" step with the big 6-digit code + Copy + a
"Waiting for them to join…" spinner (and Cancel). The native screen broadcast
starts only when the helper actually joins with that code (meeting-peer-joined) —
matching the remote-support mental model.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>