Artifact: Critical Path — Checkout Redesign

Aurora Checkout Redesign -- critical path -- exercises co-04.

Path	Sum (days)
2.1 -> 2.2 -> 3.1 -> 3.2 -> 3.3 (critical)	4+3+5+3+2 = 17
1.1 -> 3.1 -> 3.2 -> 3.3	3+5+3+2 = 13
1.2 -> 3.1 -> 3.2 -> 3.3	3+5+3+2 = 13
1.3 -> 3.1 -> 3.2 -> 3.3	2+5+3+2 = 12
2.1 -> 2.2 -> 2.3	4+3+2 = 9

Critical path: 2.1 Cart persistence rework -> 2.2 Order summary UI -> 3.1 E2E test suite -> 3.2 Load test -> 3.3 Feature-flag rollout, 17 working days, zero slack. Every other path carries slack relative to this one; delaying any task on the critical path by one day delays the project by one day.