fix: localize customer-facing errors

internal/httpapi/response_test.go

@@ -0,0 +1,24 @@
+package httpapi
+
+import "testing"
+
+func TestLocalizedAPIErrorMessage(t *testing.T) {
+	tests := []struct {
+		name    string
+		reason  string
+		message string
+		want    string
+	}{
+		{name: "login password", reason: "LOGIN_PASSWORD_INVALID", message: "login password is invalid", want: "登录密码不正确"},
+		{name: "known validation", reason: "PHONE_INVALID_FORMAT", message: "validation failed", want: "手机号码格式不正确"},
+		{name: "preserve chinese", reason: "CUSTOM_REASON", message: "自定义中文提示", want: "自定义中文提示"},
+		{name: "hide unknown english", reason: "CUSTOM_REASON", message: "unexpected dependency error", want: "请求失败，请稍后重试"},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if got := localizedAPIErrorMessage(test.reason, test.message); got != test.want {
+				t.Fatalf("localizedAPIErrorMessage() = %q, want %q", got, test.want)
+			}
+		})
+	}
+}