Snapshot Beep + WAV UI before Pomodoro rewrite.

Keep LEDC tones, TF WAV playback, and compact list layout as a tagged baseline.

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

include/wav_player.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <Arduino.h>
+#include <stdint.h>
+
+void wav_player_init();
+void wav_player_stop();
+bool wav_player_is_playing();
+bool wav_player_play_path(const char *path);
+void wav_player_set_volume(uint8_t percent); // 0-100, maps to SetGain
+void wav_player_tick(); // no-op if task handles; kept for API
+const char *wav_player_status();