Prioritizing Bugs by Severity

Commvault Command Center displays defects that QA engineers must review in a consistent order. Implement a function that ranks defects by severity first, impact second, and creation time third.

Formal Specification

Write prioritize_defects(defects), where defects is a list of dictionaries. Each dictionary contains:

• id: a unique string identifying the defect
• severity: one of "Critical", "High", "Medium", or "Low"
• impact: one of "Widespread", "Major", "Limited", or "Minimal"
• created_at: a non-negative integer timestamp, where a smaller value means the defect was created earlier

Return a list of defect IDs ordered by these rules:

1. Higher severity appears first: Critical, High, Medium, Low.
2. For equal severity, higher impact appears first: Widespread, Major, Limited, Minimal.
3. For equal severity and impact, older defects appear first, based on smaller created_at.
4. If all three values are equal, preserve the original input order.

Do not modify the input list or its dictionaries.