feat: add __init__.py files to enable module imports

Add __init__.py files to vibevoice/modular and vibevoice/processor
directories to properly export classes and enable package imports.

This allows users to import the package after installation:
- from vibevoice import VibeVoiceStreamingForConditionalGenerationInference
- from vibevoice.modular import VibeVoiceStreamingConfig
- from vibevoice.processor import VibeVoiceStreamingProcessor

Fixes import errors when using `pip install -e .`

vibevoice/modular/__init__.py

@@ -0,0 +1,14 @@
+# vibevoice/modular/__init__.py
+from .modeling_vibevoice_streaming_inference import VibeVoiceStreamingForConditionalGenerationInference
+from .configuration_vibevoice_streaming import VibeVoiceStreamingConfig
+from .modeling_vibevoice_streaming import VibeVoiceStreamingModel, VibeVoiceStreamingPreTrainedModel
+from .streamer import AudioStreamer, AsyncAudioStreamer
+
+__all__ = [
+    "VibeVoiceStreamingForConditionalGenerationInference",
+    "VibeVoiceStreamingConfig",
+    "VibeVoiceStreamingModel",
+    "VibeVoiceStreamingPreTrainedModel",
+    "AudioStreamer",
+    "AsyncAudioStreamer",
+]