feat: 회원가입 프로필 단계에 학년 필드 추가

- GRADE_OPTIONS 상수 + isHighGrade 헬퍼 (src/lib/grade.ts)
- ProfileStep에 학년 Select 추가 (필수)
- RegisterRequest 타입에 grade 추가
- 위저드 상태 + reducer에 grade 반영

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ImTotem

src/lib/grade.ts

@@ -0,0 +1,11 @@
+export const GRADE_OPTIONS = [
+  { value: "1", label: "1학년" },
+  { value: "2", label: "2학년" },
+  { value: "3", label: "3학년" },
+  { value: "4", label: "4학년" },
+  { value: "grad", label: "대학원" },
+];
+
+export function isHighGrade(grade: string): boolean {
+  return ["3", "4", "grad"].includes(grade);
+}

src/pages/register/RegisterPage.tsx

@@ -25,13 +25,14 @@ interface WizardState {
   department: string;
   studentId: string;
   phone: string;
+  grade: string;
   schoolEmail: string;
   track: string;
 }
 
 type WizardAction =
   | { type: "SET_GOOGLE"; googleToken: string; googleName: string }
-  | { type: "SET_PROFILE"; name: string; department: string; studentId: string; phone: string }
+  | { type: "SET_PROFILE"; name: string; department: string; studentId: string; phone: string; grade: string }
   | { type: "SET_EMAIL"; schoolEmail: string }
   | { type: "SET_TRACK"; track: string }
   | { type: "GO_BACK" };
@@ -57,7 +58,7 @@ function reducer(state: WizardState, action: WizardAction): WizardState {
         googleName: action.googleName,
       };
     case "SET_PROFILE":
-      return { ...state, step: 3, name: action.name, department: action.department, studentId: action.studentId, phone: action.phone };
+      return { ...state, step: 3, name: action.name, department: action.department, studentId: action.studentId, phone: action.phone, grade: action.grade };
     case "SET_EMAIL":
       return { ...state, step: 4, schoolEmail: action.schoolEmail };
     case "SET_TRACK":
@@ -82,6 +83,7 @@ export function RegisterPage() {
     department: "",
     studentId: "",
     phone: "",
+    grade: "",
     schoolEmail: "",
     track: "",
   });
@@ -98,6 +100,7 @@ export function RegisterPage() {
       school_email: state.schoolEmail,
       phone: state.phone,
       track,
+      grade: state.grade,
     });
   };
 
@@ -131,8 +134,8 @@ export function RegisterPage() {
           <ProfileStep
             defaultName={state.name || state.googleName}
             onBack={() => dispatch({ type: "GO_BACK" })}
-            onComplete={(name, department, studentId, phone) =>
-              dispatch({ type: "SET_PROFILE", name, department, studentId, phone })
+            onComplete={(name, department, studentId, phone, grade) =>
+              dispatch({ type: "SET_PROFILE", name, department, studentId, phone, grade })
             }
           />
         )}

src/pages/register/steps/ProfileStep.tsx

@@ -3,11 +3,19 @@ import { ArrowLeft } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from "@/components/ui/select";
+import { GRADE_OPTIONS } from "@/lib/grade";
 
 interface ProfileStepProps {
   defaultName: string;
   onBack: () => void;
-  onComplete: (name: string, department: string, studentId: string, phone: string) => void;
+  onComplete: (name: string, department: string, studentId: string, phone: string, grade: string) => void;
 }
 
 function formatPhone(value: string): string {
@@ -21,6 +29,7 @@ export function ProfileStep({ defaultName, onBack, onComplete }: ProfileStepProp
   const [department, setDepartment] = useState("");
   const [studentId, setStudentId] = useState("");
   const [phone, setPhone] = useState("");
+  const [grade, setGrade] = useState("");
 
   return (
     <div className="space-y-4">
@@ -64,10 +73,23 @@ export function ProfileStep({ defaultName, onBack, onComplete }: ProfileStepProp
           onChange={(e) => setPhone(formatPhone(e.target.value))}
         />
       </div>
+      <div className="space-y-2">
+        <Label>학년</Label>
+        <Select value={grade} onValueChange={(v) => setGrade(v ?? "")}>
+          <SelectTrigger>
+            <SelectValue placeholder="학년 선택" />
+          </SelectTrigger>
+          <SelectContent>
+            {GRADE_OPTIONS.map((opt) => (
+              <SelectItem key={opt.value} value={opt.value}>{opt.label}</SelectItem>
+            ))}
+          </SelectContent>
+        </Select>
+      </div>
       <Button
         className="w-full"
-        onClick={() => onComplete(name, department, studentId, phone)}
-        disabled={!name.trim() || !department.trim() || !studentId.trim() || phone.replace(/\D/g, "").length < 7}
+        onClick={() => onComplete(name, department, studentId, phone, grade)}
+        disabled={!name.trim() || !department.trim() || !studentId.trim() || phone.replace(/\D/g, "").length < 7 || !grade}
       >
         다음
       </Button>

src/types/auth.ts

@@ -40,6 +40,7 @@ export interface RegisterRequest {
   school_email: string;
   phone: string;
   track: string;
+  grade: string;
 }
 
 export interface MessageResponse {