refactor: AdminController에 GenerationService를 이용하여 기수를 조회, 수정 하는 기능을 추가 (DASOMBE-16)

Author: junjinyun

src/main/java/dmu/dasom/api/global/admin/controller/AdminController.java

@@ -9,6 +9,7 @@
 import dmu.dasom.api.domain.email.enums.MailType;
 import dmu.dasom.api.global.dto.PageResponse;
 
+import dmu.dasom.api.global.generation.service.GenerationService;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
 import io.swagger.v3.oas.annotations.media.Content;
@@ -30,6 +31,7 @@ public class AdminController {
 
     private final ApplicantService applicantService;
     private final RecruitService recruitService;
+    private final GenerationService generationService;
 
     // 지원자 조회
     @Operation(summary = "지원자 전체 조회")
@@ -102,6 +104,24 @@ public ResponseEntity<ApplicantDetailsResponseDto> updateApplicantStatus(
         return ResponseEntity.ok(applicantService.updateApplicantStatus(id, request));
     }
 
+    // 기수 조회
+    @Operation(summary = "현재 저장된 기수 조회")
+    @GetMapping("/generation")
+    public ResponseEntity<String> getCurrentGeneration() {
+        String currentGeneration = generationService.getCurrentGeneration();
+        return ResponseEntity.ok(currentGeneration);
+    }
+
+    // 기수 수정
+    @Operation(summary = "기수 수정")
+    @PatchMapping("/generation")
+    public ResponseEntity<Void> updateGeneration(
+            @RequestParam @Parameter(description = "새로운 기수 (예: '1기')") String generationValue
+    ) {
+        generationService.saveOrUpdateGeneration(generationValue);
+        return ResponseEntity.ok().build();
+    }
+
     // 모집 일정 수정
     @Operation(summary = "모집 일정 수정")
     @ApiResponses(value = {