feat: add cross-indicator compound signal detection
KSvend+1: Claude Opus 4.6 (1M context)
ae4c60c
Implements compound signal module with 4 detection patterns:
- land_conversion: NDVI decline + settlement growth
- flood_event: SAR backscatter decrease + water increase
- drought_stress: NDVI decline + water decline + SAR increase
- displacement_pressure: settlement growth adjacent to vegetation loss
Includes overlap calculation, confidence tagging, and comprehensive tests.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
