refactor: 简化画风选择卡片，移除选中/未选中双图切换逻辑

画风卡片改为统一使用单张图片，删除 active 状态图片资源，
简化 StyleSelectView 组件数据结构和模板渲染逻辑。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/views/public/create/views/StyleSelectView.vue

@@ -27,7 +27,7 @@ export default { name: 'StyleSelectView' }
 
           <div class="style-preview">
             <img
-              :src="selected === s.styleId ? s.imgActive : s.img"
+              :src="s.img"
               :alt="s.styleName"
               class="style-preview-img"
             />
@@ -60,15 +60,11 @@ import {
 import PageHeader from '@/components/aicreate/PageHeader.vue'
 import { useAicreateStore } from '@/stores/aicreate'
 
-// 导入画风图片：{style}-normal.png 未选中，{style}-active.png 选中
+// 导入画风图片
 import styleCartoonNormal from '@/assets/images/style-cartoon-normal.png'
-import styleCartoonActive from '@/assets/images/style-cartoon-active.png'
 import styleWatercolorNormal from '@/assets/images/style-watercolor-normal.png'
-import styleWatercolorActive from '@/assets/images/style-watercolor-active.png'
 import styleInkNormal from '@/assets/images/style-ink-normal.png'
-import styleInkActive from '@/assets/images/style-ink-active.png'
 import stylePencilNormal from '@/assets/images/style-pencil-normal.png'
-import stylePencilActive from '@/assets/images/style-pencil-active.png'
 
 const router = useRouter()
 const store = useAicreateStore()
@@ -78,22 +74,20 @@ interface StyleItem {
   styleId: string
   styleName: string
   desc: string
-  /** 未选中态图片 */
+  /** 风格图片 */
   img: string
-  /** 选中态图片 */
-  imgActive: string
   /** hidden=true 时暂不展示，后续开发开放 */
   hidden?: boolean
 }
 
 const styles: StyleItem[] = [
-  { styleId: 'style_cartoon',    styleName: '卡通风格', desc: '色彩鲜明，充满童趣', img: styleCartoonNormal,    imgActive: styleCartoonActive },
-  { styleId: 'style_watercolor', styleName: '水彩风格', desc: '柔和透明，梦幻浪漫', img: styleWatercolorNormal, imgActive: styleWatercolorActive },
-  { styleId: 'style_ink',        styleName: '水墨国风', desc: '古韵悠长，意境深远', img: styleInkNormal,        imgActive: styleInkActive },
-  { styleId: 'style_pencil',     styleName: '彩铅风格', desc: '细腻温暖，自然亲切', img: stylePencilNormal,     imgActive: stylePencilActive },
+  { styleId: 'style_cartoon',    styleName: '卡通风格', desc: '色彩鲜明，充满童趣', img: styleCartoonNormal },
+  { styleId: 'style_watercolor', styleName: '水彩风格', desc: '柔和透明，梦幻浪漫', img: styleWatercolorNormal },
+  { styleId: 'style_ink',        styleName: '水墨国风', desc: '古韵悠长，意境深远', img: styleInkNormal },
+  { styleId: 'style_pencil',     styleName: '彩铅风格', desc: '细腻温暖，自然亲切', img: stylePencilNormal },
   // 油画、剪贴画暂不开放，后续开发后去掉 hidden 即可
-  { styleId: 'style_oilpaint',   styleName: '油画风格', desc: '色彩浓郁，质感丰富', img: '', imgActive: '', hidden: true },
-  { styleId: 'style_collage',    styleName: '剪贴画',   desc: '趣味拼贴，创意满满', img: '', imgActive: '', hidden: true },
+  { styleId: 'style_oilpaint',   styleName: '油画风格', desc: '色彩浓郁，质感丰富', img: '', hidden: true },
+  { styleId: 'style_collage',    styleName: '剪贴画',   desc: '趣味拼贴，创意满满', img: '', hidden: true },
 ]
 
 /** 页面可见的风格列表 */