Add Pomodoro UI with 1/3/5/10 presets and custom keypad.

Replace Beep/WAV list screen with a timer; pick duration via presets or Set numpad (1-99 min), and keep selectable alarm sounds.

Co-authored-by: Cursor <cursoragent@cursor.com>

include/ui.h

@@ -5,9 +5,6 @@
 
 void ui_create();
 void ui_update(const SdCardInfo &info);
+void ui_tick(); // refresh timer + fire alarm sound
 void ui_refresh_audio_buttons();
-void ui_refresh_lists();
 void ui_set_touch_debug(int16_t lx, int16_t ly, bool down);
-
-// 0=Beep 1=WAV
-uint8_t ui_active_tab();