Update API documentation and enhance server configuration

- Added server configurations for local and production environments in `main.py`.
- Removed outdated authentication and generation API documentation files.
- Updated documentation structure to reflect the removal of deprecated API endpoints.
- Adjusted links in the quick start and developer setup documentation to point to the new API reference.
- Enhanced global CSS styles for improved theming support.

backend/main.py

@@ -34,6 +34,10 @@ app = FastAPI(
     title="voicebox API",
     description="Production-quality Qwen3-TTS voice cloning API",
     version=__version__,
+    servers=[
+        {"url": "http://localhost:8000", "description": "Local development server"},
+        {"url": "http://localhost:17493", "description": "Production server"},
+    ],
 )
 
 # CORS middleware