feat(real-world-vfc-slice): add labeled OpenSSL/Firefox/Chromium/curl pair corpus

Harvest 176 isolated vuln-vs-fix functions (109 CVEs, 352 training rows)
into benchmarks/pairs/vfc with provenance and a JSONL training manifest.
Score the slice as an honesty dashboard (ousast pairs --slice vfc);
keep the pair gate on the local fixtures only.

benchmarks/pairs/vfc/openssl-cve-2023-0216/fixed.c

@@ -0,0 +1,21 @@
+/* Provenance: openssl/openssl STACK_OF (fixed).
+ * repo: openssl/openssl
+ * commit: 80253dbdc92bec584f4a9866b43f8674156d838a
+ * parent: 625faca931957719c76fb16094cf5b6e0debe23f
+ * commit_url: https://github.com/openssl/openssl/commit/80253dbdc92bec584f4a9866b43f8674156d838a
+ * cve: CVE-2023-0216
+ * license: Apache-2.0
+ * function: STACK_OF
+ * relpath: crypto/pkcs7/pk7_lib.c
+ */
+
+static STACK_OF(X509) *pkcs7_get_signer_certs(const PKCS7 *p7)
+{
+    if (p7->d.ptr == NULL)
+        return NULL;
+    if (PKCS7_type_is_signed(p7))
+        return p7->d.sign->cert;
+    if (PKCS7_type_is_signedAndEnveloped(p7))
+        return p7->d.signed_and_enveloped->cert;
+    return NULL;
+}