feat: basecamp-project skill

.pi/gsd/templates/retrospective.md

@@ -0,0 +1,54 @@
+# Project Retrospective
+
+*A living document updated after each milestone. Lessons feed forward into future planning.*
+
+## Milestone: v{version} - {name}
+
+**Shipped:** {date}
+**Phases:** {count} | **Plans:** {count} | **Sessions:** {count}
+
+### What Was Built
+- {Key deliverable 1}
+- {Key deliverable 2}
+- {Key deliverable 3}
+
+### What Worked
+- {Efficiency win or successful pattern}
+- {What went smoothly}
+
+### What Was Inefficient
+- {Missed opportunity}
+- {What took longer than expected}
+
+### Patterns Established
+- {New pattern or convention that should persist}
+
+### Key Lessons
+1. {Specific, actionable lesson}
+2. {Another lesson}
+
+### Cost Observations
+- Model mix: {X}% opus, {Y}% sonnet, {Z}% haiku
+- Sessions: {count}
+- Notable: {efficiency observation}
+
+---
+
+## Cross-Milestone Trends
+
+### Process Evolution
+
+| Milestone | Sessions | Phases | Key Change                |
+| --------- | -------- | ------ | ------------------------- |
+| v{X}      | {N}      | {M}    | {What changed in process} |
+
+### Cumulative Quality
+
+| Milestone | Tests | Coverage | Zero-Dep Additions |
+| --------- | ----- | -------- | ------------------ |
+| v{X}      | {N}   | {Y}%     | {count}            |
+
+### Top Lessons (Verified Across Milestones)
+
+1. {Lesson verified by multiple milestones}
+2. {Another cross-validated lesson}