Fix integration tests: correct vault derivation index and debug test failures

internal/vault/secrets.go

@@ -63,10 +63,31 @@ func (v *Vault) ListSecrets() ([]string, error) {
 }
 
 // isValidSecretName validates secret names according to the format [a-z0-9\.\-\_\/]+
+// but with additional restrictions:
+// - No leading or trailing slashes
+// - No double slashes
+// - No names starting with dots
 func isValidSecretName(name string) bool {
 	if name == "" {
 		return false
 	}
+
+	// Check for leading/trailing slashes
+	if strings.HasPrefix(name, "/") || strings.HasSuffix(name, "/") {
+		return false
+	}
+
+	// Check for double slashes
+	if strings.Contains(name, "//") {
+		return false
+	}
+
+	// Check for names starting with dot
+	if strings.HasPrefix(name, ".") {
+		return false
+	}
+
+	// Check the basic pattern
 	matched, _ := regexp.MatchString(`^[a-z0-9\.\-\_\/]+$`, name)
 	return matched
 }