refactor: 전체 프론트엔드 하드코딩 색상 → CSS 변수 일괄 치환

447+ 파일, 4500+ 줄 변경:
- gray-* → border/bg-muted/text-foreground/text-muted-foreground
- blue-* → primary/ring
- red-* → destructive
- green-* → emerald (일관성)
- indigo-* → primary
- yellow/orange → amber (통일)
- dark mode 변형도 시맨틱 토큰으로 변환

Made-with: Cursor

frontend/app/(main)/multilang/page.tsx

@@ -385,13 +385,13 @@ export default function MultiLangPage() {
                   </div>
 
                   <div className="flex items-end">
-                    <div className="text-sm text-gray-600">검색 결과: {filteredLangKeys.length}건</div>
+                    <div className="text-sm text-muted-foreground">검색 결과: {filteredLangKeys.length}건</div>
                   </div>
                 </div>
               </div>
 
               <div className="mb-4 flex items-center justify-between">
-                <div className="text-sm text-gray-600">전체: {filteredLangKeys.length}건</div>
+                <div className="text-sm text-muted-foreground">전체: {filteredLangKeys.length}건</div>
               </div>
 
               <DataTable
@@ -417,7 +417,7 @@ export default function MultiLangPage() {
                 {languages.map((lang) => (
                   <div key={lang.langCode} className="rounded-lg border p-4">
                     <div className="font-semibold">{lang.langName}</div>
-                    <div className="text-sm text-gray-600">{lang.langNative}</div>
+                    <div className="text-sm text-muted-foreground">{lang.langNative}</div>
                     <Badge variant={lang.isActive === "Y" ? "default" : "secondary"} className="mt-2">
                       {lang.isActive === "Y" ? "활성" : "비활성"}
                     </Badge>
@@ -440,7 +440,7 @@ export default function MultiLangPage() {
                     <h3 className="mb-2 font-semibold">{company.name}</h3>
                     <div className="space-y-1">
                       {menus.map((menu) => (
-                        <div key={menu.code} className="text-sm text-gray-600">
+                        <div key={menu.code} className="text-sm text-muted-foreground">
                           {menu.name}
                         </div>
                       ))}