Add bounded OLED boot identity animation

src/local_boot_animation.h

@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-3.0-only */
+/* Bounded boot animation for the optional local OLED. */
+
+#pragma once
+
+#include "esp_err.h"
+
+/* Plays the OLED-only startup identity animation; a missing display is nonfatal. */
+esp_err_t local_boot_animation_play(void);