Fix library diversity and auto-automation issues

Problem: System was stuck using single all_tracks folder, causing:
- No bucket sampling diversity (all files in 1 folder)
- Repetitive sample selection
- No coherence between sections
- Fades/volumes not auto-applied

Fixes:
1. Changed DEFAULT_LIBRARY from all_tracks to organized_samples
   - server.py: Updated SAMPLES_DIR
   - sample_manager.py: Updated base_dir
   - health_check.py: Added organized_samples as primary paths

2. organized_samples structure enables T013 bucket sampling:
   - loops/bass: 34 samples
   - loops/synth: 43 samples
   - loops/vocal: 24 samples
   - oneshots/kick: 20 samples
   - oneshots/perc: 35 samples
   - Each subfolder < 15 files = perfect for bucket sampling

3. Added auto-automation to generate_song():
   - Fade-in 4 bars for kick/bass/hat (intro)
   - Build curve: music tracks 0.5 -> 0.9 (32-40 bars)
   - Reverb automation: 0% -> 40% -> 0% on atmos/pad/vocal
   - apply_automation parameter (default True)

4. Each track now gets diverse samples from different subfolders:
   - Bass from loops/bass (34 options)
   - Synth from loops/synth (43 options)
   - Drums from oneshots/ (kick, perc, snare)

Coverage wheel will now track usage across 20+ subfolders instead of 1.
Diversity memory will work correctly with proper family tracking per folder.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

AbletonMCP_AI/MCP_Server/sample_manager.py

@@ -923,7 +923,7 @@ def get_manager(base_dir: Optional[str] = None) -> SampleManager:
         if base_dir is None:
             # FIX: Use absolute path to avoid junction/hardlink issues
             PROGRAM_DATA_DIR = Path("C:/ProgramData/Ableton/Live 12 Suite/Resources/MIDI Remote Scripts")
-            base_dir = str(PROGRAM_DATA_DIR / "librerias" / "all_tracks")
+            base_dir = str(PROGRAM_DATA_DIR / "librerias" / "organized_samples")
         _manager = SampleManager(base_dir)
     return _manager