Incoming-call greeting was silently dropped: audio CMD_PLAY gated on
phone.c's debounced phone_is_offhook(), which lags/misses the pickup
while the bell rings, but the incoming flow established off-hook only
via the raw SLIC poll in conversation.c. The two flags desynced and
playback was skipped as 'on-hook' though the handset was up.
Gate playback on the real SHK line (slic_is_offhook) instead — the
single source of truth. Remove all hook forcing (s_hook_override,
phone_force_offhook, /debug/offhook): the SHK contact is reliable in
hardware, so the firmware must trust it, never override it. Builds
clean (ESP-IDF v5.4.4).
clement