Add signal quality version tracking to database

- Added signalQualityVersion field to Trade model
- Tracks which scoring logic version was used for each trade
- v1: Original logic (price position < 5% threshold)
- v2: Added volume compensation for low ADX
- v3: CURRENT - Stricter logic requiring ADX > 18 for extreme positions (< 15%)

This enables future analysis to:
- Compare performance between logic versions
- Filter trades by scoring algorithm
- Data-driven improvements based on clean datasets

All new trades will be marked as v3. Old trades remain null/v1 for comparison.

prisma/migrations/20251107114250_add_signal_quality_version/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "Trade" ADD COLUMN     "signalQualityVersion" TEXT DEFAULT 'v1';