feat: add precise diagnostics and optional client copy logging controls

cmd/go-omni/apigen/testdata/configuration/consumer_test.go

@@ -91,3 +91,23 @@ func TestConfigurationCheckProcess(t *testing.T) {
 		t.Fatal(err, string(out))
 	}
 }
+
+func TestGeneratedModuleFieldDiagnostic(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "config.yaml")
+	t.Setenv("EXAMPLE_LOG_LEVEL", "invalid-private-level")
+	if err := os.WriteFile(path, []byte("server:\n  log:\n    level: '${EXAMPLE_LOG_LEVEL}'\n"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	err := run(context.Background(), path)
+	var d *omniConfig.Error
+	if !errors.As(err, &d) || d.Field != "server.log.level" || d.Line != 3 || d.Env != "EXAMPLE_LOG_LEVEL" || !strings.Contains(d.Reason, "debug") || strings.Contains(err.Error(), "invalid-private-level") {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(path, []byte("server:\n  log:\n    timeZone: Asia/Shanghai\n"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	cfg, err := config.Load(path)
+	if err != nil || cfg.Server.Log.TimeZone != "Asia/Shanghai" {
+		t.Fatal(err)
+	}
+}