docs(architecture): baseline current design (#109)

Capture the brownfield architecture and its relationship to the project vision.\n\n- add the current-state SAD and five retrospective ADRs\n- classify vision vectors against implementation evidence\n- record requirements, risks, gates, and construction handoff

.aiwg/reports/abm-gate-report.md

@@ -0,0 +1,15 @@
+# Architecture Baseline Milestone Gate Report
+
+**Status:** PASS  
+**Date:** 2026-07-20
+
+| Criterion | Status | Evidence |
+| --- | --- | --- |
+| SAD exists and is baselined | PASS | `architecture/software-architecture-doc.md`; current-state, >1,000 words |
+| At least three ADRs | PASS | ADR-001 through ADR-005 |
+| Use-case architectural coverage | PASS | SAD traceability covers UC-001 through UC-005 |
+| Test strategy exists | PASS | `testing/test-strategy.md` |
+| No unmitigated blocking architecture risk | PASS | R-01 has enforced controls; weakening them is explicitly release-blocking |
+| Vision/current-state separation | PASS | ADR-005 and `architecture/vision-alignment.md` |
+
+The architecture is baselined for maintenance and controlled evolution. “Construction ready” means the brownfield team can prioritize alignment work; it does not relabel experimental features as stable.