2026-04-06 18:21:32,261 [INFO] ============================================================
2026-04-06 18:21:32,261 [INFO] STUDY 3: Sustained Spread Widening — Streaming Mode
2026-04-06 18:21:32,261 [INFO] Dates: 21, Sequential processing (memory-safe)
2026-04-06 18:21:32,261 [INFO] ============================================================