feat(audio): add USB Audio Host (UAC 1.0) support

Add TinyUSB Host Audio class driver supporting UAC 1.0 devices.

Features:
- Support multiple Audio Streaming (AS) interfaces with independent format storage
- Support both IN (Microphone) and OUT (Speaker) endpoints
- Per-AS interface format info: channels, sample rate, bit resolution
- Support Feature Unit volume control
- Support sampling frequency get/set
- Add host/audio_host example for STM32F407 discovery board
- Support mono-to-stereo conversion for loopback

Changes:
- Add src/class/audio/audio_host.c and audio_host.h
- Register AUDIO driver in usbh.c
- Add CFG_TUH_AUDIO macro in tusb_option.h
- Add host/audio_host example with CMake and Makefile build support

Tested with Jabra USB headset (stereo speaker + mono microphone) on STM32F407 disco.

1 files changed, 26 insertions, 0 deletions

diff --git a/examples/host/audio_host/src/app.h b/examples/host/audio_host/src/app.h
new file mode 100644
index 000000000..a807aeaa6
--- /dev/null
+++ b/examples/host/audio_host/src/app.h
@@ -0,0 +1,26 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2025 TinyUSB contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ */
+
+#ifndef TUSB_TINYUSB_EXAMPLES_APP_H
+#define TUSB_TINYUSB_EXAMPLES_APP_H
+
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+void audio_app_task(void);
+
+#endif