Refactor response package structure: move CurrentSongDetailRecordDto and TopTrackResponseDto to dto.response package; update imports in SpotifyService and SpotifyMapper

Rename artifactId from 'mcp-server' to 'mcp_server' in pom.xml

Update dependencies in pom.xml and remove unnecessary logging in SpotifyService

Implement user data handling with UserDataInterceptor and related classes; refactor SpotifyService to use thread-local API key

Update application.yaml and pom.xml for configuration adjustments

Add CurrentSongDetail and CurrentSongDetailRecordDto models; update SpotifyService to fetch current song details

Update README.md to enhance project description and features

Update playback_controller description for clarity

Add PlayBackState enum and implement controlPlayBack method in SpotifyService

Refactor SpotifyService to use injected API token for authentication

Add API key parameter and update authorization header in SpotifyService

Update .gitignore to include environment files

Update .gitignore to prevent tracking of the .env file

Add .env to .gitignore and update application.yaml for environment variable support

Update run script to set JAVA_HOME for custom JRE creation