docs: accept leader summary notification architecture

.project-docs/60-reflection/cases/20260907-integrate-leader-summaries-84c1d7ea__integration-source-baseline.md

@@ -0,0 +1,19 @@
+# Reflection: Integration source baseline
+
+## Trigger
+
+The first leader-summary Integration worktree was created from `origin/main` and then merged the completed Feature commit. Because `check_doc_drift.py` compares the Integration tree with its recorded base, the Feature's required task record appeared as a foreign task-owned change even though Integration had not edited it.
+
+## Lesson
+
+For one completed Feature, the Integration task should start from the Feature commit that already contains its task record. The target default branch must then be verified as an ancestor or reconciled before canonical edits. This preserves the source record as read-only while making the drift boundary mechanically accurate.
+
+## Action
+
+- Restarted the Integration task from source commit `1a3ab63` after preserving the first attempt and normally releasing its lock.
+- Added the single-Feature baseline rule to `.project-docs/05-agent-entry/integration-gate.md`.
+- Kept the occupied `main` worktree untouched and used no force, reset, stash, or history rewrite.
+
+## Reuse
+
+Apply this baseline choice to future one-Feature integrations. Multiple-source integrations still require an explicitly reviewed combined strategy; do not bypass foreign task-record checks.

.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