Refactor TTS provider management and enhance documentation

- Renamed `bundled-mlx` to `apple-mlx` for clarity in provider types.
- Updated the ProviderSettings component to reflect the new provider naming.
- Improved logging for provider startup and error handling in the backend.
- Added scripts for building and installing PyTorch CPU and CUDA providers locally.
- Enhanced the documentation to include details on TTS provider architecture and development setup.

providers/pytorch-cpu/tts-provider-pytorch-cpu.spec

@@ -0,0 +1,48 @@
+# -*- mode: python ; coding: utf-8 -*-
+from PyInstaller.utils.hooks import collect_data_files
+from PyInstaller.utils.hooks import collect_submodules
+from PyInstaller.utils.hooks import copy_metadata
+
+datas = []
+hiddenimports = ['backend', 'backend.backends', 'backend.backends.pytorch_backend', 'backend.config', 'backend.utils.audio', 'backend.utils.cache', 'backend.utils.progress', 'backend.utils.hf_progress', 'backend.utils.tasks', 'torch', 'transformers', 'qwen_tts', 'qwen_tts.inference', 'qwen_tts.inference.qwen3_tts_model', 'qwen_tts.inference.qwen3_tts_tokenizer', 'qwen_tts.core', 'qwen_tts.cli', 'pkg_resources.extern', 'fastapi', 'uvicorn', 'soundfile', 'numpy', 'librosa']
+datas += collect_data_files('qwen_tts')
+datas += copy_metadata('qwen-tts')
+hiddenimports += collect_submodules('qwen_tts')
+hiddenimports += collect_submodules('jaraco')
+
+
+a = Analysis(
+    ['main.py'],
+    pathex=['/Users/jamespine/Projects/voicebox'],
+    binaries=[],
+    datas=datas,
+    hiddenimports=hiddenimports,
+    hookspath=[],
+    hooksconfig={},
+    runtime_hooks=[],
+    excludes=['torch.utils.tensorboard', 'tensorboard', 'triton', 'torch._dynamo', 'torch._inductor', 'torch.testing', 'torch.utils.benchmark', 'IPython', 'matplotlib', 'PIL', 'cv2', 'torchvision', 'torchaudio'],
+    noarchive=False,
+    optimize=0,
+)
+pyz = PYZ(a.pure)
+
+exe = EXE(
+    pyz,
+    a.scripts,
+    a.binaries,
+    a.datas,
+    [],
+    name='tts-provider-pytorch-cpu',
+    debug=False,
+    bootloader_ignore_signals=False,
+    strip=False,
+    upx=True,
+    upx_exclude=[],
+    runtime_tmpdir=None,
+    console=True,
+    disable_windowed_traceback=False,
+    argv_emulation=False,
+    target_arch=None,
+    codesign_identity=None,
+    entitlements_file=None,
+)