feat(universal-form-modal): Select 필드 직접 입력(Combobox) 모드 추가

SelectOptionConfig에 allowCustomInput 옵션 추가
FieldDetailSettingsModal에 "직접 입력 허용" Switch UI 추가
CascadingSelectField에 Combobox 모드 구현 (Popover+Command)
SelectField에 Combobox 모드 구현
목록 선택과 직접 입력 동시 지원

frontend/lib/registry/components/universal-form-modal/UniversalFormModalComponent.tsx

@@ -19,7 +19,9 @@ import {
   AlertDialogTitle,
 } from "@/components/ui/alert-dialog";
 import { Card, CardContent, CardHeader, CardTitle, CardDescription } from "@/components/ui/card";
-import { ChevronDown, ChevronUp, ChevronRight, Plus, Trash2, Loader2 } from "lucide-react";
+import { ChevronDown, ChevronUp, ChevronRight, Plus, Trash2, Loader2, Check, ChevronsUpDown } from "lucide-react";
+import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
+import { Command, CommandEmpty, CommandGroup, CommandInput, CommandItem, CommandList } from "@/components/ui/command";
 import { toast } from "sonner";
 import { cn } from "@/lib/utils";
 import { apiClient } from "@/lib/api/client";
@@ -42,6 +44,7 @@ import { TableSectionRenderer } from "./TableSectionRenderer";
 
 /**
  * 🔗 연쇄 드롭다운 Select 필드 컴포넌트
+ * allowCustomInput이 true이면 Combobox 형태로 직접 입력 가능
  */
 interface CascadingSelectFieldProps {
   fieldId: string;
@@ -51,6 +54,7 @@ interface CascadingSelectFieldProps {
   onChange: (value: string) => void;
   placeholder?: string;
   disabled?: boolean;
+  allowCustomInput?: boolean;
 }
 
 const CascadingSelectField: React.FC<CascadingSelectFieldProps> = ({
@@ -61,12 +65,20 @@ const CascadingSelectField: React.FC<CascadingSelectFieldProps> = ({
   onChange,
   placeholder,
   disabled,
+  allowCustomInput = false,
 }) => {
+  const [open, setOpen] = useState(false);
+  const [inputValue, setInputValue] = useState(value || "");
   const { options, loading } = useCascadingDropdown({
     config,
     parentValue,
   });
 
+  // value가 외부에서 변경되면 inputValue도 동기화
+  useEffect(() => {
+    setInputValue(value || "");
+  }, [value]);
+
   const getPlaceholder = () => {
     if (!parentValue) {
       return config.emptyParentMessage || "상위 항목을 먼저 선택하세요";
@@ -82,6 +94,79 @@ const CascadingSelectField: React.FC<CascadingSelectFieldProps> = ({
 
   const isDisabled = disabled || !parentValue || loading;
 
+  // Combobox 형태 (직접 입력 허용)
+  if (allowCustomInput) {
+    return (
+      <Popover open={open} onOpenChange={setOpen}>
+        <PopoverTrigger asChild>
+          <div className="relative w-full">
+            <Input
+              id={fieldId}
+              value={inputValue}
+              onChange={(e) => {
+                setInputValue(e.target.value);
+                onChange(e.target.value);
+              }}
+              placeholder={getPlaceholder()}
+              disabled={isDisabled}
+              className="w-full pr-8"
+            />
+            <Button
+              type="button"
+              variant="ghost"
+              size="sm"
+              className="absolute right-0 top-0 h-full px-2 hover:bg-transparent"
+              onClick={() => !isDisabled && setOpen(!open)}
+              disabled={isDisabled}
+            >
+              {loading ? (
+                <Loader2 className="h-4 w-4 animate-spin text-muted-foreground" />
+              ) : (
+                <ChevronsUpDown className="h-4 w-4 text-muted-foreground" />
+              )}
+            </Button>
+          </div>
+        </PopoverTrigger>
+        <PopoverContent className="w-[--radix-popover-trigger-width] p-0" align="start">
+          <Command>
+            <CommandInput placeholder="검색..." className="h-9" />
+            <CommandList>
+              <CommandEmpty>
+                {!parentValue
+                  ? config.emptyParentMessage || "상위 항목을 먼저 선택하세요"
+                  : config.noOptionsMessage || "선택 가능한 항목이 없습니다"}
+              </CommandEmpty>
+              <CommandGroup>
+                {options
+                  .filter((option) => option.value && option.value !== "")
+                  .map((option) => (
+                    <CommandItem
+                      key={option.value}
+                      value={option.label}
+                      onSelect={() => {
+                        setInputValue(option.label);
+                        onChange(option.value);
+                        setOpen(false);
+                      }}
+                    >
+                      <Check
+                        className={cn(
+                          "mr-2 h-4 w-4",
+                          value === option.value ? "opacity-100" : "opacity-0"
+                        )}
+                      />
+                      {option.label}
+                    </CommandItem>
+                  ))}
+              </CommandGroup>
+            </CommandList>
+          </Command>
+        </PopoverContent>
+      </Popover>
+    );
+  }
+
+  // 기본 Select 형태 (목록에서만 선택)
   return (
     <Select value={value || ""} onValueChange={onChange} disabled={isDisabled}>
       <SelectTrigger id={fieldId} className="w-full" size="default">
@@ -1503,6 +1588,7 @@ export function UniversalFormModalComponent({
                 onChange={onChangeHandler}
                 placeholder={field.placeholder || "선택하세요"}
                 disabled={isDisabled}
+                allowCustomInput={field.selectOptions?.allowCustomInput}
               />
             );
           }
@@ -1534,6 +1620,7 @@ export function UniversalFormModalComponent({
                 onChange={onChangeHandler}
                 placeholder={field.placeholder || "선택하세요"}
                 disabled={isDisabled}
+                allowCustomInput={field.selectOptions?.allowCustomInput}
               />
             );
           }
@@ -2243,6 +2330,7 @@ export function UniversalFormModalComponent({
 }
 
 // Select 필드 컴포넌트 (옵션 로딩 포함)
+// allowCustomInput이 true이면 Combobox 형태로 직접 입력 가능
 interface SelectFieldProps {
   fieldId: string;
   value: any;
@@ -2256,6 +2344,10 @@ interface SelectFieldProps {
 function SelectField({ fieldId, value, onChange, optionConfig, placeholder, disabled, loadOptions }: SelectFieldProps) {
   const [options, setOptions] = useState<{ value: string; label: string }[]>([]);
   const [loading, setLoading] = useState(false);
+  const [open, setOpen] = useState(false);
+  const [inputValue, setInputValue] = useState(value || "");
+  
+  const allowCustomInput = optionConfig?.allowCustomInput || false;
 
   useEffect(() => {
     if (optionConfig) {
@@ -2266,6 +2358,82 @@ function SelectField({ fieldId, value, onChange, optionConfig, placeholder, disa
     }
   }, [fieldId, optionConfig, loadOptions]);
 
+  // value가 외부에서 변경되면 inputValue도 동기화
+  useEffect(() => {
+    // 선택된 값이 있으면 해당 라벨을 표시, 없으면 value 그대로 표시
+    const selectedOption = options.find((opt) => opt.value === value);
+    setInputValue(selectedOption ? selectedOption.label : value || "");
+  }, [value, options]);
+
+  // Combobox 형태 (직접 입력 허용)
+  if (allowCustomInput) {
+    return (
+      <Popover open={open} onOpenChange={setOpen}>
+        <PopoverTrigger asChild>
+          <div className="relative w-full">
+            <Input
+              id={fieldId}
+              value={inputValue}
+              onChange={(e) => {
+                setInputValue(e.target.value);
+                onChange(e.target.value);
+              }}
+              placeholder={loading ? "로딩 중..." : placeholder}
+              disabled={disabled || loading}
+              className="w-full pr-8"
+            />
+            <Button
+              type="button"
+              variant="ghost"
+              size="sm"
+              className="absolute right-0 top-0 h-full px-2 hover:bg-transparent"
+              onClick={() => !disabled && !loading && setOpen(!open)}
+              disabled={disabled || loading}
+            >
+              {loading ? (
+                <Loader2 className="h-4 w-4 animate-spin text-muted-foreground" />
+              ) : (
+                <ChevronsUpDown className="h-4 w-4 text-muted-foreground" />
+              )}
+            </Button>
+          </div>
+        </PopoverTrigger>
+        <PopoverContent className="w-[--radix-popover-trigger-width] p-0" align="start">
+          <Command>
+            <CommandInput placeholder="검색..." className="h-9" />
+            <CommandList>
+              <CommandEmpty>선택 가능한 항목이 없습니다</CommandEmpty>
+              <CommandGroup>
+                {options
+                  .filter((option) => option.value && option.value !== "")
+                  .map((option) => (
+                    <CommandItem
+                      key={option.value}
+                      value={option.label}
+                      onSelect={() => {
+                        setInputValue(option.label);
+                        onChange(option.value);
+                        setOpen(false);
+                      }}
+                    >
+                      <Check
+                        className={cn(
+                          "mr-2 h-4 w-4",
+                          value === option.value ? "opacity-100" : "opacity-0"
+                        )}
+                      />
+                      {option.label}
+                    </CommandItem>
+                  ))}
+              </CommandGroup>
+            </CommandList>
+          </Command>
+        </PopoverContent>
+      </Popover>
+    );
+  }
+
+  // 기본 Select 형태 (목록에서만 선택)
   return (
     <Select value={value || ""} onValueChange={onChange} disabled={disabled || loading}>
       <SelectTrigger size="default">

frontend/lib/registry/components/universal-form-modal/modals/FieldDetailSettingsModal.tsx

@@ -480,6 +480,31 @@ export function FieldDetailSettingsModal({
                         </HelpText>
                       </div>
 
+                      {/* 직접 입력 허용 - 모든 Select 타입에 공통 적용 */}
+                      <div className="flex items-center justify-between pt-2 border-t">
+                        <div className="flex flex-col">
+                          <span className="text-[10px] font-medium">직접 입력 허용</span>
+                          <span className="text-[9px] text-muted-foreground">
+                            목록 선택 + 직접 타이핑 가능
+                          </span>
+                        </div>
+                        <Switch
+                          checked={localField.selectOptions?.allowCustomInput || false}
+                          onCheckedChange={(checked) =>
+                            updateField({
+                              selectOptions: {
+                                ...localField.selectOptions,
+                                allowCustomInput: checked,
+                              },
+                            })
+                          }
+                        />
+                      </div>
+                      <HelpText>
+                        활성화 시 드롭다운 목록에서 선택하거나, 직접 값을 입력할 수 있습니다.
+                        목록에 없는 새로운 값도 입력 가능합니다.
+                      </HelpText>
+
                       {localField.selectOptions?.type === "table" && (
                         <div className="space-y-3 pt-2 border-t">
                           <HelpText>테이블 참조: DB 테이블에서 옵션 목록을 가져옵니다.</HelpText>

frontend/lib/registry/components/universal-form-modal/types.ts

@@ -32,6 +32,11 @@ export interface SelectOptionConfig {
     noOptionsMessage?: string; // 옵션 없음 메시지
     clearOnParentChange?: boolean; // 부모 변경 시 값 초기화 (기본: true)
   };
+  
+  // 직접 입력 허용 (모든 Select 타입에 공통 적용)
+  // true: Combobox 형태로 목록 선택 + 직접 입력 가능
+  // false/undefined: 기본 Select 형태로 목록에서만 선택 가능
+  allowCustomInput?: boolean;
 }
 
 // 채번규칙 설정