feat: Enhance AI tagging schema and instructions for audio characteristics

Commit notes

- Updated the AI tagging schema to enforce a maximum of 5 single-word tags. - Revised instructions to specify the requirement for exactly 5 descriptive tags, emphasizing lowercase format without hyphens or spaces. - Improved tag generation logic to deduplicate and limit tags to single words only, ensuring a maximum of 5 tags returned. - Adjusted example tags in the instructions for clarity and relevance.