feat(redact): add gitleaks rule for OpenRouter API keys

OpenRouter API keys have the shape sk-or-v1-<64 hex>. The existing
entropy-based redactor requires Shannon entropy above 4.5 bits/byte,
but pure-hex strings max out at 4.0 bits/byte, so these keys would
pass through redaction unmasked if they ever appeared in logs,
errors, or telemetry. Add a dedicated gitleaks rule keyed on the
sk-or-v1- prefix plus a unit test exercising redaction in a Bearer
authorization context. The test constructs its fixture at runtime
so the literal token shape never appears in committed source.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/crates/fabro-redact/data/gitleaks.toml

@@ -2546,6 +2546,13 @@ regex = '''\b(sk-[a-zA-Z0-9]{20}T3BlbkFJ[a-zA-Z0-9]{20})(?:['|\"|\n|\r|\s|\x60|;
 entropy = 3
 keywords = ["t3blbkfj"]
 
+[[rules]]
+id = "openrouter-api-key"
+description = "Found an OpenRouter API Key, posing a risk of unauthorized access to LLM provider routing and billing."
+regex = '''\b(sk-or-v1-[0-9a-f]{64})(?:['|\"|\n|\r|\s|\x60|;]|$)'''
+entropy = 3
+keywords = ["sk-or-v1-"]
+
 [[rules]]
 id = "openshift-user-token"
 description = "Found an OpenShift user token, potentially compromising an OpenShift/Kubernetes cluster."

lib/crates/fabro-redact/src/lib.rs

@@ -117,6 +117,24 @@ mod tests {
         );
     }
 
+    #[test]
+    fn redact_string_openrouter_api_key() {
+        // Constructed at runtime so the literal token shape does not appear
+        // in source and trip secret-scanning push protection.
+        let prefix = format!("sk-{}{}-v1-", "o", "r");
+        let body = "0123456789abcdef".repeat(4);
+        let input = format!("Authorization: Bearer {prefix}{body}");
+        let result = redact_string(&input);
+        assert!(
+            result.contains("REDACTED"),
+            "expected REDACTED in: {result}"
+        );
+        assert!(
+            !result.contains(&prefix),
+            "raw OpenRouter key prefix should not survive: {result}"
+        );
+    }
+
     #[test]
     fn redact_string_private_key() {
         let input =