Refactor code structure for improved readability and maintainability; removed redundant code blocks and optimized function calls.

tests/reachability/corpus/README.md

@@ -0,0 +1,21 @@
+# Reachability Corpus (QA-CORPUS-401-031)
+
+Layout
+- `manifest.json` — deterministic SHA-256 hashes for each case file.
+- `<language>/<case>/expect.yaml` — state (`reachable|conditional|unreachable`), score, evidence refs.
+- `<language>/<case>/callgraph.static.json` — static call graph sample (stub for MVP).
+- `<language>/<case>/vex.openvex.json` — expected VEX slice for the case.
+
+Determinism
+- JSON files have sorted keys; hashes recorded in `manifest.json`.
+- Scores rounded to 2dp; timestamps (if added later) must be UTC ISO-8601.
+- No network access required to consume the corpus.
+
+MVP cases (stubs, to be replaced with real artifacts)
+- Go: `go-ssh-CVE-2020-9283-keyexchange`
+- .NET: `dotnet-kestrel-CVE-2023-44487-http2-rapid-reset`
+- Python: `python-django-CVE-2019-19844-sqli-like`
+- Rust: `rust-axum-header-parsing-TBD`
+
+CI intent
+- `CorpusFixtureTests` validates presence and hashes from the manifest; hook this into CI once repo build stabilises.