Rename integration from spotify_search to spotify_voice_assistant

Rename integration for consistent branding:
- User-facing name: "Spotify Voice Assistant"
- Integration name: "Spotify Voice Assistant Search"
- Domain: spotify_voice_assistant

Changes:
- Rename custom_components/spotify_search/ to spotify_voice_assistant/
- Update domain in manifest.json and __init__.py
- Update all service references in examples
- Update all documentation references

examples/configuration.yaml

@@ -2,10 +2,10 @@
 # Add to your configuration.yaml
 
 # Spotify Voice Assistant Integration
-spotify_search:
+spotify_voice_assistant:
 
 # Optional: Enable debug logging as needed
 logger:
   default: info
   logs:
-    custom_components.spotify_search: debug
+    custom_components.spotify_voice_assistant: debug