Upgrade to Hybrid Architecture v3 (Fast Lane + Deep Dive)

Fix: extract Sentinel-2 vegetation_indices_summary and SAR crop_health

Pass skip_llm=True to Sentinel2, enforce 5 calls/minute limit

Add 5-key Gemini API fallback, conversation memory, historical trends, and zone recommendations

Full Developer Spec implementation: Priority-based Multi-Stage Reasoning

Add satellite band data injection from HF Space APIs (SAR, Sentinel-2)