Record performance audit baseline evidence

docs/roadmap/implementation.md

@@ -64,7 +64,7 @@ configuration semantics, dependencies, Go minimum, or release gates.
    equality risks exceed the selected scope. Existing clones and linked traces
    stay in place. No new dependency, pool, or package-global mutable cache is needed.
 
-## Stage 1: Confirm the baseline and semantic evidence
+## Stage 1: Confirm the baseline and semantic evidence — Complete
 
 Scope: orientation and test-only evidence, with no optimization yet.
 
@@ -84,6 +84,25 @@ Done: baseline checks recorded and semantic test owners identified. Existing
 contracts/tests are authoritative; reference algorithms add equivalence evidence,
 not new public guarantees. A documentation-only stage needs documentation checks.
 
+### Evidence
+
+- Current revision: `52793301ba80eb49f91956009e60cd812f92e94c`; planning baseline:
+  `0c77deed05417edb32f42c7bf24df2fdc2581a25`. The working tree was clean, and
+  production Go files match the audit baseline `48619de024d794cf41e90b171b7fcbe609dcd437`.
+- `GOTOOLCHAIN=local go version`: `go1.26.8 linux/amd64`.
+  `GOTOOLCHAIN=local ./scripts/check.sh`: passed (`go test ./...`, `go vet ./...`,
+  and `go build ./...`, in addition to formatting and whitespace checks). No
+  environmental limitations encountered; no benchmark campaign was repeated.
+- Existing semantic coverage includes numeric/key-index and escaped path shapes
+  (`path_test.go`, `provenance_test.go`, `override_test.go`), removed/history
+  paths (`metadata_test.go`, `resolution_test.go`, `inheritance_history_test.go`),
+  nested and sequence-contained inheritance (`inheritance_test.go`,
+  `inheritance_walk_test.go`), detached callback/metadata records
+  (`callback_ownership_test.go`, `resolution_test.go`, `metadata_test.go`), and
+  independent loads (`provenance_test.go`). Differential reference helpers are
+  deferred to the first stage that consumes each algorithm so they can remain
+  small and bounded.
+
 ## Stage 2: Make presence-only queries lightweight
 
 Roadmap candidate 1. Owner: `internal/engine/metadata.go`.