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/processor/__init__.py

@@ -0,0 +1,11 @@
+# vibevoice/processor/__init__.py
+from .vibevoice_processor import VibeVoiceProcessor
+from .vibevoice_streaming_processor import VibeVoiceStreamingProcessor
+from .vibevoice_tokenizer_processor import VibeVoiceTokenizerProcessor, AudioNormalizer
+
+__all__ = [
+    "VibeVoiceProcessor",
+    "VibeVoiceStreamingProcessor",
+    "VibeVoiceTokenizerProcessor",
+    "AudioNormalizer",
+]