Backend:
- Added prompt_structure JSON column to clips DB (migration in init_db)
- Updated GenerateRequest model with optional prompt_structure dict
- build_prompt() method combines structured fields into single prompt:
'Generate a track with the following elements:\n\n**Style:** [style]\n...'
- create_clip() accepts and stores prompt_structure JSON
- get_clips()/get_clip() parse prompt_structure back to dict
Frontend:
- New StructuredPromptEditor component with 8 collapsible fields:
Style, Timbre, Structure, Mood, Tempo, Instrumentation, Effects, Additional
- Fields show filled/empty state with colored dots
- Expand/collapse individual fields
- 'Expand All' button
- Counter: 'X of 8 fields filled'
- Generator component updated with Basic/Advanced mode toggle (Pro only)
- Basic: single textarea (works for both models)
- Advanced: StructuredPromptEditor (Pro only)
- Mode resets to Basic when switching to Clip Preview
- DetailPanel shows structured prompt breakdown when present
- Each filled field shown in its own labeled box
- Style, Timbre, Structure, Mood, Tempo, Instrumentation, Effects, Additional
- Clip interface updated with prompt_structure field across all components
Architecture KB and Tasks KB updated.