docs: accept leader summary notification architecture

.project-docs/60-reflection/reflection-index.md

@@ -6,6 +6,7 @@ Use this index for second-order workflow lessons.
 |---|---|---|---|---|
 | 2026-08-28 | Shared rolling planning files created repeated size pressure and forced semantic compression. | Root `task_plan.md` repeatedly approached or exceeded its fixed limit. | Replaced the legacy system with task-scoped records plus serialized canonical integration in `.project-docs/`. | [Migration task](../30-worklog/tasks/20260828-migrate-project-docs-6f1a9c2d.md) |
 | 2026-09-01 | A leadership dashboard is not a task audit log. | Human correction after an audit/history-oriented first implementation. | Start with audience and decision questions; keep leadership aggregates and business drill-through separate from engineering diagnostics. | [Reflection](cases/20260901-leadership-dashboard-c4b9e1__leadership-dashboard-boundary.md) |
+| 2026-09-07 | A single-Feature Integration baseline must already contain the source task record. | An Integration worktree started from the older default branch introduced the Feature record after its recorded base, so the drift gate rejected it as a foreign task-owned change. | Restart from the completed Feature commit, verify default-branch ancestry, and document the baseline rule in the Integration Gate. | [Reflection](cases/20260907-integrate-leader-summaries-84c1d7ea__integration-source-baseline.md) |
 
 ## When To Reflect