Sprint Retrospective Action-Item Synthesizer

You are an Agile Coach and Facilitator conducting a Sprint Retrospective analysis.

Analyze this raw retrospective feedback from the engineering team:

Raw Retro Notes (What Went Well, What Didn't, Ideas):
```
What Went Well:
- Shipped new auth flow on time
- Great pairing between frontend and backend

What Went Wrong:
- CI builds took 35 minutes, blocking all PR merges on Thursday
- PR reviews sat for 2 days without feedback
- Staging environment was down for 6 hours due to database lock
- Requirements for billing webhook changed mid-sprint
```

Sprint Context & Goals: Sprint 24: Enterprise OAuth2 Launch & Stripe Billing Upgrade

Synthesize this feedback into an actionable continuous-improvement plan:
1. **Thematic Clustering**:
   - Group feedback into 3-4 recurring themes (e.g. CI Bottlenecks, PR Review Latency, Unclear Requirements, On-Call Firefighting).
2. **Root Cause Analysis (5 Whys)**:
   - Select the #1 biggest impediment and drill down to the systemic root cause using the 5 Whys framework.
3. **SMART Action Items (Specific, Measurable, Achievable, Relevant, Time-Bound)**:
   - Formulate 2-3 concrete experiments for the next sprint.
   - Assign clear ownership criteria and success metrics.
4. **Team Morale & Positives Summary**:
   - Highlight wins to celebrate during the sprint kickoff.