fix: add CGO build tags to consistency tests, remove unused isHex function

internal/auth/api_key.go

@@ -373,13 +373,3 @@ func GenerateNewAPIKey(admin bool, roles []string, permissions map[string]bool)
 
 	return plaintext, entry, nil
 }
-
-// isHex checks if a string contains only hex characters
-func isHex(s string) bool {
-	for _, c := range s {
-		if !((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F')) {
-			return false
-		}
-	}
-	return len(s) > 0
-}

tests/integration/consistency/cmd/update.go

@@ -1,3 +1,6 @@
+//go:build cgo
+// +build cgo
+
 // Command update computes expected hashes for fixtures using the reference Go implementation
 package main
 

tests/integration/consistency/dataset_hash_test.go

@@ -1,3 +1,6 @@
+//go:build cgo
+// +build cgo
+
 package consistency
 
 import (