Fix test-count claim in audit log's sarif.go finding

Round-3 review caught it: sarif_test.go has 16 top-level Test
functions, not 12.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017Req4a3SADus6KRYrmYqKg

Author: claude

docs/development/architecture-audit.md

@@ -33,7 +33,7 @@ Clean surfaces, verified:
   `Formatter` interface as `JSONFormatter` and
   `TextFormatter`. It is documented in
   `docs/reference/cli/check.md` and `fix.md`
-  (`-f sarif`). 12 tests lock its shape.
+  (`-f sarif`). 16 tests lock its shape.
 - `internal/pack` is a small registry package,
   mirroring `internal/starter`.
 - `internal/rules/externallink`'s wasm/net build-tag