feat(banner): 生成并上线四张高端大气轮播图（现代中式与数字底座、精工中台、AI智能体、产品矩阵）

public/assets/addons/official/css/modern_nhc.css

@@ -378,31 +378,26 @@ img {
 /* 轮播图幻灯片不同主题背景与中式意境光影 (浅色高雅、通透水墨微晕) */
 .nhc-slide-theme-1 {
   background: 
-    radial-gradient(circle at 50% 18%, rgba(37, 99, 235, 0.08) 0%, transparent 48%),
-    radial-gradient(circle at 82% 65%, rgba(6, 182, 212, 0.07) 0%, transparent 45%),
-    radial-gradient(circle at 18% 75%, rgba(124, 58, 237, 0.04) 0%, transparent 40%),
-    linear-gradient(180deg, #FFFFFF 0%, #F8FAFC 100%);
+    linear-gradient(90deg, rgba(255, 255, 255, 0.96) 0%, rgba(255, 255, 255, 0.90) 42%, rgba(255, 255, 255, 0.15) 100%),
+    url('../images/banners/banner_lead.jpg') right center / cover no-repeat;
 }
 
 .nhc-slide-theme-2 {
   background: 
-    radial-gradient(circle at 80% 25%, rgba(37, 99, 235, 0.09) 0%, transparent 50%),
-    radial-gradient(circle at 20% 60%, rgba(6, 182, 212, 0.06) 0%, transparent 45%),
-    linear-gradient(180deg, #F8FAFC 0%, #FFFFFF 100%);
+    linear-gradient(90deg, rgba(255, 255, 255, 0.96) 0%, rgba(255, 255, 255, 0.90) 42%, rgba(255, 255, 255, 0.15) 100%),
+    url('../images/banners/banner_craft.jpg') right center / cover no-repeat;
 }
 
 .nhc-slide-theme-3 {
   background: 
-    radial-gradient(circle at 50% 20%, rgba(6, 182, 212, 0.09) 0%, transparent 50%),
-    radial-gradient(circle at 80% 80%, rgba(124, 58, 237, 0.06) 0%, transparent 50%),
-    linear-gradient(180deg, #FFFFFF 0%, #F8FAFC 100%);
+    linear-gradient(90deg, rgba(255, 255, 255, 0.96) 0%, rgba(255, 255, 255, 0.90) 42%, rgba(255, 255, 255, 0.15) 100%),
+    url('../images/banners/banner_agent.jpg') right center / cover no-repeat;
 }
 
 .nhc-slide-theme-4 {
   background: 
-    radial-gradient(circle at 20% 30%, rgba(124, 58, 237, 0.08) 0%, transparent 50%),
-    radial-gradient(circle at 80% 70%, rgba(37, 99, 235, 0.08) 0%, transparent 55%),
-    linear-gradient(180deg, #F8FAFC 0%, #FFFFFF 100%);
+    linear-gradient(90deg, rgba(255, 255, 255, 0.96) 0%, rgba(255, 255, 255, 0.90) 42%, rgba(255, 255, 255, 0.15) 100%),
+    url('../images/banners/banner_matrix.jpg') right center / cover no-repeat;
 }
 
 /* 轮播图切换过渡微动画 */