Address hash module review feedback

Agent-Logs-Url: https://github.com/version-fox/vfox/sessions/2766badf-41e8-4039-b36c-df0c7668b145

Co-authored-by: bytemain <13938334+bytemain@users.noreply.github.com>

Author: Copilot

internal/plugin/luai/module/hash/hash.go

@@ -122,12 +122,16 @@ func pushFileVerify(L *lua.LState, filepath, expected, algorithm string) int {
 	return 1
 }
 
-func DigestFile(filepath, algorithm string) (string, error) {
+func DigestFile(filepath, algorithm string) (digest string, err error) {
 	file, err := os.Open(filepath)
 	if err != nil {
 		return "", err
 	}
-	defer file.Close()
+	defer func() {
+		if closeErr := file.Close(); err == nil && closeErr != nil {
+			err = closeErr
+		}
+	}()
 
 	hasher, err := newHash(algorithm)
 	if err != nil {

internal/plugin/luai/module/hash/hash_test.go

@@ -26,7 +26,7 @@ import (
 
 func TestHashModule(t *testing.T) {
 	tempDir := t.TempDir()
-	testFile := filepath.Join(tempDir, "archive.tar.gz")
+	testFile := filepath.Join(tempDir, "sample-file.txt")
 	if err := os.WriteFile(testFile, []byte("hello world"), 0644); err != nil {
 		t.Fatal(err)
 	}
@@ -87,7 +87,7 @@ func TestHashModuleErrors(t *testing.T) {
 	`
 
 	tempDir := t.TempDir()
-	testFile := filepath.Join(tempDir, "archive.tar.gz")
+	testFile := filepath.Join(tempDir, "sample-file.txt")
 	if err := os.WriteFile(testFile, []byte("hello world"), 0644); err != nil {
 		t.Fatal(err)
 	}