UIScreen gains onDisplayOff()/onDisplayOn() hooks. JoystickUITask tracks
display state and dispatches them on transition — at top of loop()
(catches display.c's auto-off, which fires behind our back) and right
after _display.turnOn() in the wake path (immediate resume).
Override in SnakeScreen and GPSSettingsScreen: stop their periodic
k_timers while the screen is off, restart on wake. Game state and
GPS-fix state are preserved across sleep. Snake doesn't crash into a
wall five seconds after the screen sleeps anymore.
Other screen timers (Countdown alarm, Contacts/Admin response timeout,
the global lock timer) intentionally keep running — their job is to
fire while the user is idle.
Also: wake-from-off now reschedules the lock timer if not already
locked, so a keypress near the end of the lock window gives you a
fresh LOCK_AFTER_MS instead of being immediately re-locked.
s_scan_sent (one-shot per boot) becomes s_last_scan_ms; RepeatersScreen
onEnter() re-runs the discover if there has never been a scan or the
last one is older than REPEATER_RESCAN_AFTER_MS (60s). Walking away
and returning now gives a fresh list instead of stale results.
Also fixes the manual KEY_ENTER_LONG rescan: after Phase C removed
the poll() that re-checked the flag, just unsetting it no longer
triggered anything. Now it calls doScan() directly.
UIScreen gains onEnter()/onExit() lifecycle hooks; poll() and the
_curr->poll() call in the main loop are removed. Each screen with
periodic or deadline-based work owns its own k_timer:
- one-shot timers: Splash dismiss, Countdown alarm, Contacts ping
timeout, RepeaterAdmin cmd/login timeout, Unread preview expiry
- periodic timers: Snake tick, GPSSettings sample
- onEnter()-only: Repeaters discover, Doom start
- deleted: Home, Stopwatch (were empty)
Timer ISR callbacks only signal _task->notify() — never mutate
screen state. Main-thread render() handles transitions. Setting
_curr now fires onExit on the outgoing screen and onEnter on the
incoming one, so timers are scoped to screen lifetime and can't
fire stale events on the wrong screen.
liquidraver