The lag was NOT the workout session: once the workout kept the watch reachable,
both sides re-sent the whole course over the live channel on every stroke, flooding
WatchConnectivity. Fix: full state (round+course) only on the coalesced
applicationContext backstop; live sendMessage carries round-only. Watch sends
round-only always (phone owns the course). Re-enabled the workout so the Action
Button works with minimal setup (Settings > Action Button > Workout > Golf Round).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>