refactor: 설정 패널 UI 개선 - Collapsible로 정리

- 필드 그룹을 Collapsible로 변경하여 펼침/접힘 가능
- 항목 표시 설정도 Collapsible로 분리하여 깔끔하게 정리
- 그룹 제목에 displayItems 개수 표시
- 기본적으로 그룹은 펼쳐진 상태, 표시 설정은 접힌 상태
- ChevronDown/ChevronRight 아이콘으로 펼침 상태 표시
- 복잡한 설정을 단계적으로 볼 수 있어 가독성 대폭 향상

frontend/lib/registry/components/selected-items-detail-input/SelectedItemsDetailInputConfigPanel.tsx

@@ -7,7 +7,8 @@ import { Button } from "@/components/ui/button";
 import { Checkbox } from "@/components/ui/checkbox";
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
 import { Card, CardContent } from "@/components/ui/card";
-import { Plus, X } from "lucide-react";
+import { Collapsible, CollapsibleContent, CollapsibleTrigger } from "@/components/ui/collapsible";
+import { Plus, X, ChevronDown, ChevronRight } from "lucide-react";
 import { SelectedItemsDetailInputConfig, AdditionalFieldDefinition, FieldGroup, DisplayItem, DisplayItemType, EmptyBehavior, DisplayFieldFormat } from "./types";
 import { Command, CommandEmpty, CommandGroup, CommandInput, CommandItem } from "@/components/ui/command";
 import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
@@ -46,6 +47,12 @@ export const SelectedItemsDetailInputConfigPanel: React.FC<SelectedItemsDetailIn
   // 🆕 필드 그룹 상태
   const [localFieldGroups, setLocalFieldGroups] = useState<FieldGroup[]>(config.fieldGroups || []);
   
+  // 🆕 그룹별 펼침/접힘 상태
+  const [expandedGroups, setExpandedGroups] = useState<Record<string, boolean>>({});
+  
+  // 🆕 그룹별 표시 항목 설정 펼침/접힘 상태
+  const [expandedDisplayItems, setExpandedDisplayItems] = useState<Record<string, boolean>>({});
+  
   // 🆕 원본 테이블 선택 상태
   const [sourceTableSelectOpen, setSourceTableSelectOpen] = useState(false);
   const [sourceTableSearchValue, setSourceTableSearchValue] = useState("");
@@ -621,20 +628,40 @@ export const SelectedItemsDetailInputConfigPanel: React.FC<SelectedItemsDetailIn
         </p>
 
         {localFieldGroups.map((group, index) => (
-          <Card key={group.id} className="border-2">
-            <CardContent className="space-y-2 pt-3 sm:space-y-3 sm:pt-4">
-              <div className="flex items-center justify-between">
-                <span className="text-xs font-semibold text-gray-700 sm:text-sm">그룹 {index + 1}</span>
-                <Button
-                  type="button"
-                  variant="ghost"
-                  size="icon"
-                  onClick={() => removeFieldGroup(group.id)}
-                  className="h-6 w-6 text-red-500 hover:text-red-700 sm:h-7 sm:w-7"
-                >
-                  <X className="h-3 w-3 sm:h-4 sm:w-4" />
-                </Button>
-              </div>
+          <Collapsible
+            key={group.id}
+            open={expandedGroups[group.id] ?? true}
+            onOpenChange={(open) => setExpandedGroups(prev => ({ ...prev, [group.id]: open }))}
+          >
+            <Card className="border-2">
+              <CardContent className="space-y-2 p-3 sm:space-y-3 sm:p-4">
+                <div className="flex items-center justify-between">
+                  <CollapsibleTrigger asChild>
+                    <Button variant="ghost" size="sm" className="h-auto p-0 hover:bg-transparent">
+                      <div className="flex items-center gap-2">
+                        {expandedGroups[group.id] ?? true ? (
+                          <ChevronDown className="h-4 w-4" />
+                        ) : (
+                          <ChevronRight className="h-4 w-4" />
+                        )}
+                        <span className="text-xs font-semibold sm:text-sm">
+                          그룹 {index + 1}: {group.title || group.id}
+                        </span>
+                      </div>
+                    </Button>
+                  </CollapsibleTrigger>
+                  <Button
+                    type="button"
+                    variant="ghost"
+                    size="icon"
+                    onClick={() => removeFieldGroup(group.id)}
+                    className="h-6 w-6 text-red-500 hover:text-red-700 sm:h-7 sm:w-7"
+                  >
+                    <X className="h-3 w-3 sm:h-4 sm:w-4" />
+                  </Button>
+                </div>
+
+                <CollapsibleContent className="space-y-2 sm:space-y-3">{/* 기존 그룹 설정 내용 */}
 
               {/* 그룹 ID */}
               <div className="space-y-1">
@@ -682,10 +709,27 @@ export const SelectedItemsDetailInputConfigPanel: React.FC<SelectedItemsDetailIn
               </div>
 
               {/* 🆕 이 그룹의 항목 표시 설정 */}
-              <div className="space-y-2 rounded-lg border-2 border-dashed border-primary/30 bg-primary/5 p-2">
-                <div className="flex items-center justify-between">
-                  <Label className="text-[10px] font-semibold sm:text-xs">항목 표시 설정</Label>
-                  <div className="flex gap-1">
+              <Collapsible
+                open={expandedDisplayItems[group.id] ?? false}
+                onOpenChange={(open) => setExpandedDisplayItems(prev => ({ ...prev, [group.id]: open }))}
+              >
+                <div className="space-y-2 rounded-lg border-2 border-dashed border-primary/30 bg-primary/5 p-2">
+                  <div className="flex items-center justify-between">
+                    <CollapsibleTrigger asChild>
+                      <Button variant="ghost" size="sm" className="h-auto p-0 hover:bg-transparent">
+                        <div className="flex items-center gap-1">
+                          {expandedDisplayItems[group.id] ? (
+                            <ChevronDown className="h-3 w-3" />
+                          ) : (
+                            <ChevronRight className="h-3 w-3" />
+                          )}
+                          <Label className="text-[10px] font-semibold sm:text-xs cursor-pointer">
+                            항목 표시 설정 ({(group.displayItems || []).length}개)
+                          </Label>
+                        </div>
+                      </Button>
+                    </CollapsibleTrigger>
+                    <div className="flex gap-1">
                     <Button
                       type="button"
                       size="sm"
@@ -719,11 +763,12 @@ export const SelectedItemsDetailInputConfigPanel: React.FC<SelectedItemsDetailIn
                   </div>
                 </div>
                 
-                <p className="text-[9px] text-muted-foreground sm:text-[10px]">
-                  이 그룹의 입력 항목이 추가되면 어떻게 표시될지 설정
-                </p>
+                <CollapsibleContent className="space-y-2">
+                  <p className="text-[9px] text-muted-foreground sm:text-[10px]">
+                    이 그룹의 입력 항목이 추가되면 어떻게 표시될지 설정
+                  </p>
 
-                {(!group.displayItems || group.displayItems.length === 0) ? (
+                  {(!group.displayItems || group.displayItems.length === 0) ? (
                   <div className="rounded border border-dashed p-2 text-center text-[10px] text-muted-foreground">
                     미설정 (모든 필드를 " / "로 구분하여 표시)
                   </div>
@@ -846,10 +891,15 @@ export const SelectedItemsDetailInputConfigPanel: React.FC<SelectedItemsDetailIn
                       </div>
                     ))}
                   </div>
-                )}
-              </div>
-            </CardContent>
-          </Card>
+                  )}
+                </CollapsibleContent>
+                </div>
+              </Collapsible>
+
+                </CollapsibleContent>
+              </CardContent>
+            </Card>
+          </Collapsible>
         ))}
 
         <Button