fix: 기본코드 등록/수정 화면 탭 안 중첩 셸 제거

- CodeKind/CodeDetail create·edit 가 view('admin/layout') 직접 사용 → 탭(iframe) 안에서 풀셸 중첩
- renderWorkPage 로 교체 + renderWorkPage 가 embed 요청이면 경로 무관하게 embed 레이아웃 사용하도록 일반화

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/Controllers/Admin/CodeDetail.php

@@ -56,14 +56,11 @@ class CodeDetail extends BaseController
 
         helper('admin');
 
-        return view('admin/layout', [
-            'title'   => '세부코드 등록 — ' . $kind->ck_name,
-            'content' => view('admin/code_detail/create', [
-                'kind'             => $kind,
-                'canPlatformScope' => $canPlatformScope,
-                'localGovernments' => $govs,
-                'effectiveLgIdx'   => admin_effective_lg_idx(),
-            ]),
+        return $this->renderWorkPage('세부코드 등록 — ' . $kind->ck_name, 'admin/code_detail/create', [
+            'kind'             => $kind,
+            'canPlatformScope' => $canPlatformScope,
+            'localGovernments' => $govs,
+            'effectiveLgIdx'   => admin_effective_lg_idx(),
         ]);
     }
 
@@ -156,12 +153,9 @@ class CodeDetail extends BaseController
 
         $kind = $this->kindModel->find($item->cd_ck_idx);
 
-        return view('admin/layout', [
-            'title'   => '세부코드 수정 — ' . ($kind->ck_name ?? ''),
-            'content' => view('admin/code_detail/edit', [
-                'item' => $item,
-                'kind' => $kind,
-            ]),
+        return $this->renderWorkPage('세부코드 수정 — ' . ($kind->ck_name ?? ''), 'admin/code_detail/edit', [
+            'item' => $item,
+            'kind' => $kind,
         ]);
     }