feat: [dev] DevToolbar 드래그 이동 + 위치 프리셋 기능 추가

- 접힌 Dev 버튼: 마우스 드래그로 자유 이동
- 펼친 툴바: 좌측 그립 아이콘으로 드래그 이동
- 3x3 위치 프리셋 그리드 (좌상/우상/중앙/좌하/우하)
- localStorage에 위치 저장 (새로고침 후에도 유지)

src/components/dev/DevToolbar.tsx

@@ -14,7 +14,7 @@
  * NEXT_PUBLIC_DEV_TOOLBAR_ENABLED=true
  */
 
-import { useState } from 'react';
+import { useState, useEffect, useCallback, useRef } from 'react';
 import { usePathname, useRouter, useSearchParams } from 'next/navigation';
 import {
   FileText,      // 견적
@@ -39,6 +39,7 @@ import {
   PackageCheck,     // 입고
   // Dev 도구 아이콘
   Layers,           // 컴포넌트 레지스트리
+  GripVertical,       // 드래그 핸들
 } from 'lucide-react';
 import { Button } from '@/components/ui/button';
 import { Badge } from '@/components/ui/badge';
@@ -102,6 +103,46 @@ const MATERIAL_STEPS: { type: DevFillPageType; label: string; icon: typeof FileT
   { type: 'receiving', label: '입고', icon: PackageCheck, path: '/material/receiving-management/new', fillEnabled: true },
 ];
 
+// ===== 위치 관리 헬퍼 =====
+const POS_KEY_MINI = 'dev-toolbar-pos-mini';
+const POS_KEY_FULL = 'dev-toolbar-pos-full';
+
+function loadPos(key: string): { x: number; y: number } | null {
+  if (typeof window === 'undefined') return null;
+  try {
+    const s = localStorage.getItem(key);
+    return s ? JSON.parse(s) : null;
+  } catch { return null; }
+}
+
+function savePos(key: string, p: { x: number; y: number }) {
+  try { localStorage.setItem(key, JSON.stringify(p)); } catch { /* noop */ }
+}
+
+function PositionGrid({ onSelect }: { onSelect: (id: string) => void }) {
+  const spots: [string, boolean, string][] = [
+    ['tl', true, '좌상단'], ['', false, ''], ['tr', true, '우상단'],
+    ['', false, ''], ['c', true, '중앙'], ['', false, ''],
+    ['bl', true, '좌하단'], ['', false, ''], ['br', true, '우하단'],
+  ];
+  return (
+    <div className="inline-grid grid-cols-3 gap-[3px] p-1 rounded bg-yellow-200/60" title="위치 프리셋">
+      {spots.map(([id, active, title], i) =>
+        active ? (
+          <button
+            key={id}
+            className="w-[7px] h-[7px] rounded-full bg-yellow-700 hover:bg-yellow-900 hover:scale-150 transition-all"
+            onClick={(e) => { e.stopPropagation(); onSelect(id); }}
+            title={title}
+          />
+        ) : (
+          <div key={`e${i}`} className="w-[7px] h-[7px] rounded-full bg-yellow-400/30" />
+        )
+      )}
+    </div>
+  );
+}
+
 export function DevToolbar() {
   const pathname = usePathname();
   const router = useRouter();
@@ -120,6 +161,67 @@ export function DevToolbar() {
   const [isExpanded, setIsExpanded] = useState(true);
   const [isLoading, setIsLoading] = useState<DevFillPageType | null>(null);
 
+  // ===== 드래그 & 위치 관리 =====
+  const containerRef = useRef<HTMLDivElement>(null);
+  const [collapsedPos, setCollapsedPos] = useState<{x: number; y: number} | null>(null);
+  const [expandedPos, setExpandedPos] = useState<{x: number; y: number} | null>(null);
+  const dragRef = useRef({ active: false, moved: false, sx: 0, sy: 0, px: 0, py: 0, target: '' as 'mini' | 'full' });
+
+  useEffect(() => {
+    setCollapsedPos(loadPos(POS_KEY_MINI) || { x: window.innerWidth - 100, y: window.innerHeight - 96 });
+    setExpandedPos(loadPos(POS_KEY_FULL) || { x: Math.max(8, (window.innerWidth - 700) / 2), y: window.innerHeight - 250 });
+  }, []);
+
+  const startDrag = useCallback((e: React.MouseEvent, target: 'mini' | 'full', pos: {x: number; y: number} | null) => {
+    if (e.button !== 0) return;
+    e.preventDefault();
+    const d = dragRef.current;
+    d.active = true; d.moved = false;
+    d.sx = e.clientX; d.sy = e.clientY;
+    d.px = pos?.x || 0; d.py = pos?.y || 0;
+    d.target = target;
+  }, []);
+
+  useEffect(() => {
+    const onMove = (e: MouseEvent) => {
+      const d = dragRef.current;
+      if (!d.active) return;
+      const dx = e.clientX - d.sx, dy = e.clientY - d.sy;
+      if (Math.abs(dx) > 3 || Math.abs(dy) > 3) d.moved = true;
+      if (!d.moved) return;
+      const p = { x: d.px + dx, y: d.py + dy };
+      if (d.target === 'mini') setCollapsedPos(p); else setExpandedPos(p);
+    };
+    const onUp = (e: MouseEvent) => {
+      const d = dragRef.current;
+      if (!d.active) return;
+      d.active = false;
+      if (d.moved) {
+        const p = { x: d.px + (e.clientX - d.sx), y: d.py + (e.clientY - d.sy) };
+        savePos(d.target === 'mini' ? POS_KEY_MINI : POS_KEY_FULL, p);
+      }
+    };
+    window.addEventListener('mousemove', onMove);
+    window.addEventListener('mouseup', onUp);
+    return () => { window.removeEventListener('mousemove', onMove); window.removeEventListener('mouseup', onUp); };
+  }, []);
+
+  const snapTo = useCallback((preset: string) => {
+    const el = containerRef.current;
+    const w = el?.offsetWidth || 700, h = el?.offsetHeight || 200;
+    const vw = window.innerWidth, vh = window.innerHeight, m = 16;
+    let p: {x: number; y: number};
+    switch (preset) {
+      case 'tl': p = { x: m, y: m }; break;
+      case 'tr': p = { x: vw - w - m, y: m }; break;
+      case 'c': p = { x: (vw - w) / 2, y: (vh - h) / 2 }; break;
+      case 'bl': p = { x: m, y: vh - h - m }; break;
+      default: p = { x: vw - w - m, y: vh - h - m }; break;
+    }
+    setExpandedPos(p);
+    savePos(POS_KEY_FULL, p);
+  }, []);
+
   // 현재 locale 추출 (유효한 locale만 인식)
   const VALID_LOCALES = ['ko', 'en'];
   const firstSegment = pathname.split('/')[1];
@@ -128,18 +230,19 @@ export function DevToolbar() {
   // mode=new 쿼리 파라미터 확인
   const isNewMode = searchParams.get('mode') === 'new';
 
-  // 비활성화 시 렌더링하지 않음
-  if (!isEnabled) return null;
+  // 비활성화 또는 위치 미초기화 시 렌더링하지 않음
+  if (!isEnabled || !collapsedPos || !expandedPos) return null;
 
-  // 숨김 상태일 때 작은 버튼만 표시
+  // 숨김 상태일 때 작은 버튼만 표시 (드래그 이동 가능)
   if (!isVisible) {
     return (
-      <div className="fixed bottom-20 right-4 z-[9999]">
+      <div className="fixed z-[9999]" style={{ left: collapsedPos.x, top: collapsedPos.y }}>
         <Button
           size="sm"
           variant="outline"
-          className="bg-yellow-100 border-yellow-400 text-yellow-800 hover:bg-yellow-200 shadow-lg"
-          onClick={() => setIsVisible(true)}
+          className="bg-yellow-100 border-yellow-400 text-yellow-800 hover:bg-yellow-200 shadow-lg cursor-grab active:cursor-grabbing select-none"
+          onMouseDown={(e) => startDrag(e, 'mini', collapsedPos)}
+          onClick={() => { if (!dragRef.current.moved) setIsVisible(true); }}
         >
           <Play className="w-4 h-4 mr-1" />
           Dev
@@ -187,11 +290,19 @@ export function DevToolbar() {
   const hasFlowData = flowData.quoteId || flowData.orderId || flowData.workOrderId || flowData.lotNo;
 
   return (
-    <div className="fixed bottom-12 left-1/2 -translate-x-1/2 z-[9999] w-[calc(100vw-1rem)] sm:w-auto sm:max-w-[calc(100vw-1rem)]">
+    <div ref={containerRef} className="fixed z-[9999] max-w-[calc(100vw-1rem)]" style={{ left: expandedPos.x, top: expandedPos.y }}>
       <div className="bg-yellow-50 border-2 border-yellow-400 rounded-lg shadow-2xl overflow-hidden">
         {/* 헤더 */}
         <div className="flex items-center justify-between px-2 sm:px-3 py-1.5 sm:py-2 bg-yellow-100 border-b border-yellow-300">
           <div className="flex items-center gap-2">
+            {/* 드래그 핸들 */}
+            <div
+              className="cursor-grab active:cursor-grabbing select-none p-0.5 rounded hover:bg-yellow-200 shrink-0"
+              onMouseDown={(e) => startDrag(e, 'full', expandedPos)}
+              title="드래그하여 이동"
+            >
+              <GripVertical className="w-4 h-4 text-yellow-600" />
+            </div>
             <Badge variant="outline" className="bg-yellow-200 border-yellow-500 text-yellow-800">
               DEV MODE
             </Badge>
@@ -236,6 +347,7 @@ export function DevToolbar() {
             )}
           </div>
           <div className="flex items-center gap-1">
+            <PositionGrid onSelect={snapTo} />
             {hasFlowData && (
               <Button
                 size="icon"