feat(design): Vibe design optimization — Hero, Bento grids, trust layer, narrative

升级全站体验：首页 Hero 改为产品视觉 + 单一 CTA 转化布局；产品矩阵/服务/方案改
为 Bento 非对称网格（ERP 2x2 大卡 + BI 1x2）；补齐信任层（可验证信号 + 来源标注）
与「问题→方法→结果」章节式叙事；新增 hero-product-visual 与 bento-grid 可复用组件；
统一动效与品牌视觉资产。新增对应单测、UJ-11 用户旅程测试并更新视觉回归基线快照。

src/app/(marketing)/about/about-content-v4.tsx

@@ -173,8 +173,14 @@ function WhoWeAreSection({ data }: { data: AboutData }) {
             transition={{ duration: 0.8, ease: EASE_OUT }}
             className="lg:col-span-5"
           >
-            <div className="text-sm font-mono tracking-[0.2em] text-text-muted uppercase mb-6">
-              Who We Are
+            <div className="flex items-center gap-4 mb-6">
+              <span className="text-4xl md:text-5xl font-black text-brand/80 font-mono leading-none tabular-nums">01</span>
+              <div>
+                <div className="text-sm font-mono tracking-[0.2em] text-text-muted uppercase">
+                  Why We Started
+                </div>
+                <div className="text-xs text-text-muted mt-1">为什么成立</div>
+              </div>
             </div>
             <h2 className="text-3xl sm:text-4xl md:text-5xl lg:text-6xl font-extrabold text-ink tracking-tight leading-[0.95] mb-8">
               {data.whoWeAreTitle || ''}
@@ -196,6 +202,15 @@ function WhoWeAreSection({ data }: { data: AboutData }) {
             transition={{ duration: 0.8, delay: 0.15, ease: EASE_OUT }}
             className="lg:col-span-7"
           >
+            <div className="flex items-center gap-4 mb-6">
+              <span className="text-4xl md:text-5xl font-black text-brand/80 font-mono leading-none tabular-nums">02</span>
+              <div>
+                <div className="text-sm font-mono tracking-[0.2em] text-text-muted uppercase">
+                  How We Work
+                </div>
+                <div className="text-xs text-text-muted mt-1">怎么做事</div>
+              </div>
+            </div>
             <div className="space-y-6 md:space-y-8">
               {values.map((value) => (
                 <div
@@ -236,8 +251,14 @@ function MilestonesSection({ data }: { data: AboutData }) {
           transition={{ duration: 0.8, ease: EASE_OUT }}
           className="max-w-3xl mb-16 sm:mb-20 md:mb-24"
         >
-          <div className="text-sm font-mono tracking-[0.2em] text-text-muted uppercase mb-6">
-            Our Journey
+          <div className="flex items-center gap-4 mb-6">
+            <span className="text-4xl md:text-5xl font-black text-brand/80 font-mono leading-none tabular-nums">03</span>
+            <div>
+              <div className="text-sm font-mono tracking-[0.2em] text-text-muted uppercase">
+                Where We Are Heading
+              </div>
+              <div className="text-xs text-text-muted mt-1">走到哪里</div>
+            </div>
           </div>
           <h2 className="text-3xl sm:text-4xl md:text-5xl lg:text-6xl font-extrabold text-ink tracking-tight leading-[0.95]">
             一路走来，<br className="sm:hidden" />步步扎实