Add AI Prompting System V2 and enhance audio generation capabilities

Commit notes

- Introduced a comprehensive AI Prompting System V2 for BeatStep's sample generation pipeline, addressing previous issues and implementing best practices. - Added genre-specific templates for Trap, Lofi, Drill, Boom Bap, and Future Bass, ensuring consistent quality and predictable outputs. - Implemented a two-pass generation system for improved intent extraction and template application. - Enhanced prompt validation with banned terms filtering and quality enforcement. - Updated the generator to optimize prompts and extract sound-specific durations, improving audio generation accuracy. - Integrated a new PromptEngineeringService for advanced prompt generation and fallback strategies. - Added tests for genre detection, prompt generation, and validation to ensure system reliability and performance. - Updated API endpoints to include genre information and improved sound generation capabilities. - Ensured backward compatibility and gradual rollout of the new system for seamless integration into existing workflows.