괄호 앞 음수 분배 스테이지 추가

lib/engine/types.ts

@@ -0,0 +1,22 @@
+export interface ParenthesisSignProblem {
+  id: string;
+  key: string;
+  multiplier: number;
+  a: number;
+  operator: "+" | "-";
+  b: number;
+  distributedA: number;
+  distributedB: number;
+  latexBefore: string;
+  latexAfter: string;
+}
+
+export interface UserAnswer {
+  a: number;
+  b: number;
+}
+
+export interface GradeResult {
+  correct: boolean;
+  correctAnswer: [number, number];
+}