[feat] update some feature

sync code of  fastrtc,
add text support through datachannel,
fix safari connect problem
support chat without camera or mic

backend/fastrtc/__init__.py

@@ -0,0 +1,76 @@
+from .credentials import (
+    get_hf_turn_credentials,
+    get_turn_credentials,
+    get_twilio_turn_credentials,
+)
+from .pause_detection import (
+    ModelOptions,
+    PauseDetectionModel,
+    SileroVadOptions,
+    get_silero_model,
+)
+from .reply_on_pause import AlgoOptions, ReplyOnPause
+from .reply_on_stopwords import ReplyOnStopWords
+from .speech_to_text import MoonshineSTT, get_stt_model
+from .stream import Stream, UIArgs
+from .text_to_speech import KokoroTTSOptions, get_tts_model
+from .tracks import (
+    AsyncAudioVideoStreamHandler,
+    AsyncStreamHandler,
+    AudioEmitType,
+    AudioVideoStreamHandler,
+    StreamHandler,
+    VideoEmitType,
+)
+from .utils import (
+    AdditionalOutputs,
+    Warning,
+    WebRTCError,
+    aggregate_bytes_to_16bit,
+    async_aggregate_bytes_to_16bit,
+    audio_to_bytes,
+    audio_to_file,
+    audio_to_float32,
+    audio_to_int16,
+    wait_for_item,
+)
+from .webrtc import (
+    WebRTC,
+)
+
+__all__ = [
+    "AsyncStreamHandler",
+    "AudioVideoStreamHandler",
+    "AudioEmitType",
+    "AsyncAudioVideoStreamHandler",
+    "AlgoOptions",
+    "AdditionalOutputs",
+    "aggregate_bytes_to_16bit",
+    "async_aggregate_bytes_to_16bit",
+    "audio_to_bytes",
+    "audio_to_file",
+    "audio_to_float32",
+    "audio_to_int16",
+    "get_hf_turn_credentials",
+    "get_twilio_turn_credentials",
+    "get_turn_credentials",
+    "ReplyOnPause",
+    "ReplyOnStopWords",
+    "SileroVadOptions",
+    "get_stt_model",
+    "MoonshineSTT",
+    "StreamHandler",
+    "Stream",
+    "VideoEmitType",
+    "WebRTC",
+    "WebRTCError",
+    "Warning",
+    "get_tts_model",
+    "KokoroTTSOptions",
+    "wait_for_item",
+    "UIArgs",
+    "ModelOptions",
+    "PauseDetectionModel",
+    "get_silero_model",
+    "SileroVadOptions",
+]