[#38] feat: GET /auth/users 엔드포인트 및 UserService.findAllUsers 추가

src/main/java/com/issueDive/controller/AuthController.java

@@ -11,6 +11,8 @@
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
+import java.util.List;
+
 
 @RestController
 @RequestMapping("/auth")
@@ -65,4 +67,14 @@ public ResponseEntity<ApiResponse<Void>> deleteUser(@PathVariable Long id){
         ApiResponse<Void> response = ApiResponse.ok(null);
         return  new ResponseEntity<>(response, HttpStatus.OK);
     }
+
+    /**
+     * Read: 전체 사용자 목록 조회
+     * @return 공통 응답 포맷 + 사용자 DTO 리스트
+     */
+    @GetMapping("/users")
+    public ResponseEntity<ApiResponse<List<UserResponseDTO>>> getAllUsers() {
+        List<UserResponseDTO> users = userService.getAllUsers();
+        return ResponseEntity.ok(ApiResponse.ok(users));
+    }
 }

src/main/java/com/issueDive/service/UserService.java

@@ -14,6 +14,8 @@
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
+import java.util.List;
+
 @Service
 @RequiredArgsConstructor
 @Transactional(readOnly = true)
@@ -76,4 +78,11 @@ public void deleteUser(Long id){
         }
         userRepository.deleteById(id);
     }
+
+    // 전체 사용자 목록 조회
+    public List<UserResponseDTO> getAllUsers() {
+        return userRepository.findAll().stream()
+                .map(u -> new UserResponseDTO(u.getId(), u.getUsername(), u.getEmail()))
+                .toList();
+    }
 }