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/lib/registry/components/date-input/DateInputComponent.tsx

@@ -402,7 +402,7 @@ export const DateInputComponent: React.FC<DateInputComponentProps> = ({
       {component.label && component.style?.labelDisplay !== false && (
         <label className="absolute -top-6 left-0 text-sm font-medium text-slate-600">
           {component.label}
-          {component.required && <span className="text-red-500">*</span>}
+          {component.required && <span className="text-destructive">*</span>}
         </label>
       )}