feat: 简化页面布局为4个清晰步骤流程

- 重构index页面为步骤式交互：上传→加载→结果→错误
- 优化用户体验：单一焦点，清晰的状态转换
- 美化UI设计：统一卡片容器，渐变背景，现代化按钮
- 完善提示词：更新为中文手办生成专用描述
- 修复SDK模型名称：gemini-2.5-flash-image
- 添加类型安全：getTaskStatus返回string[]类型

src/pages/index/index.css

@@ -1,3 +1,132 @@
-.index{
-    font-size: 1rem;
+.index {
+  min-height: 100vh;
+  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 40rpx;
+}
+
+/* 通用步骤容器 */
+.step-container {
+  background: white;
+  border-radius: 24rpx;
+  box-shadow: 0 8rpx 32rpx rgba(0, 0, 0, 0.1);
+  padding: 80rpx 60rpx;
+  text-align: center;
+  width: 100%;
+  max-width: 600rpx;
+}
+
+/* 标题样式 */
+.step-title {
+  font-size: 48rpx;
+  font-weight: bold;
+  color: #333;
+  margin-bottom: 30rpx;
+  display: block;
+}
+
+/* 描述文字 */
+.step-desc {
+  font-size: 28rpx;
+  color: #666;
+  margin-bottom: 60rpx;
+  line-height: 1.6;
+  display: block;
+}
+
+/* 上传按钮 */
+.upload-btn {
+  background: linear-gradient(45deg, #667eea, #764ba2);
+  color: white;
+  border: none;
+  border-radius: 50rpx;
+  padding: 30rpx 80rpx;
+  font-size: 32rpx;
+  font-weight: bold;
+  box-shadow: 0 6rpx 20rpx rgba(102, 126, 234, 0.4);
+  min-width: 300rpx;
+}
+
+.upload-btn:active {
+  transform: translateY(2rpx);
+  box-shadow: 0 4rpx 16rpx rgba(102, 126, 234, 0.3);
+}
+
+/* 加载动画 */
+.loading-spinner {
+  width: 80rpx;
+  height: 80rpx;
+  border: 6rpx solid #f3f3f3;
+  border-top: 6rpx solid #667eea;
+  border-radius: 50%;
+  animation: spin 1s linear infinite;
+  margin: 0 auto 40rpx;
+}
+
+@keyframes spin {
+  0% { transform: rotate(0deg); }
+  100% { transform: rotate(360deg); }
+}
+
+/* 结果网格 */
+.result-grid {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 20rpx;
+  margin-bottom: 60rpx;
+}
+
+.result-image {
+  width: 100%;
+  height: 280rpx;
+  border-radius: 16rpx;
+  object-fit: cover;
+  box-shadow: 0 4rpx 16rpx rgba(0, 0, 0, 0.1);
+}
+
+/* 重新生成按钮 */
+.restart-btn {
+  background: linear-gradient(45deg, #52c41a, #73d13d);
+  color: white;
+  border: none;
+  border-radius: 50rpx;
+  padding: 24rpx 60rpx;
+  font-size: 30rpx;
+  font-weight: bold;
+  box-shadow: 0 4rpx 16rpx rgba(82, 196, 26, 0.3);
+}
+
+.restart-btn:active {
+  transform: translateY(2rpx);
+}
+
+/* 错误描述 */
+.error-desc {
+  font-size: 26rpx;
+  color: #ff4d4f;
+  margin-bottom: 50rpx;
+  background: #fff2f0;
+  border: 1rpx solid #ffccc7;
+  border-radius: 12rpx;
+  padding: 30rpx;
+  line-height: 1.5;
+  display: block;
+}
+
+/* 重试按钮 */
+.retry-btn {
+  background: linear-gradient(45deg, #ff4d4f, #ff7875);
+  color: white;
+  border: none;
+  border-radius: 50rpx;
+  padding: 24rpx 60rpx;
+  font-size: 30rpx;
+  font-weight: bold;
+  box-shadow: 0 4rpx 16rpx rgba(255, 77, 79, 0.3);
+}
+
+.retry-btn:active {
+  transform: translateY(2rpx);
 }