[feat](trx-rs): add ft8 decoder

Co-authored-by: Codex <codex@openai.com>
Signed-off-by: Stanislaw Grams <stanislawgrams@gmail.com>

external/ft8_lib/common/audio.h

@@ -0,0 +1,18 @@
+#ifndef _INCLUDE_AUDIO_H_
+#define _INCLUDE_AUDIO_H_
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+int audio_init(void);
+void audio_list(void);
+int audio_open(const char* name);
+int audio_read(float* buffer, int num_samples);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _INCLUDE_AUDIO_H_