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/requirements/UC-005.md

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+# UC-005 — Reproduce Claims and Benchmark Results
+
+**Primary actor:** Maintainer, contributor, or evaluator  
+**Goal:** Re-derive public capability claims from committed data and detect fitting or provenance regressions.
+
+## Main Flow
+
+1. Evaluator runs claim or benchmark verification.
+2. Harness reads committed corpus, receipts, and ground truth.
+3. Scores and verdicts are recomputed.
+4. CI fails if claims, provenance, or anti-fitting invariants do not hold.
+
+**Implementation coverage:** `bench/`, `scripts/verify-claims.mjs`, model/benchmark scripts, anti-fitting tests, `.github/workflows/ci.yml`.