Removes the Bluetooth screen — the device now has just splash + Usage. Keeps
main's responsive Layout intact.
- ui: drop the Bluetooth screen, ui_cycle_screen, and SCREEN_BLUETOOTH. The
bottom spinner becomes a status line — Connected / Disconnected / Pairing…
(via ble_has_bonds()) plus the whimsical messages when connected and idle.
A "To pair / hold the power button / for 3 seconds, then release" hint shows
while disconnected so the screen isn't empty.
- main: hold-to-pair gesture (pair_tick) — hold PWR ~3s then RELEASE clears
bonds and re-advertises. Clearing on release (not while held) means holding
to power off (8s hardware shutdown) leaves the bond intact; disarms at 6s.
PWR short-press now cycles brightness on the Usage view (animations on splash).
- ble: add ble_has_bonds() for the status line.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
