refactor(detail): 合并 L3 客户案例/资质认证区块为共享组件

- 新建 CaseStudiesSection / CertificationsSection 共享组件（src/components/detail），
  合并 solution/product 逐字重复的本地实现与 service 的异类实现（卡片 motion.a
  链 /cases/<slug> 依赖尚不存在数据 → 404，违反零编造）
- bg-white → bg-bg-primary token 化（浅色零视觉差异，深色模式正确反色，对齐暗黑 Phase 2）
- 数据闸门保留：caseStudies/certifications 空时 return null，由 L3EmptyFallback 接管
- grid/flex 类直接挂 StaggerReveal，修复合并前的单列布局 bug
- 动效 0.8s → 0.7s（detail-cta-section + service CTASection），对齐 ≤700ms 约束
- 附 scripts/audit/l3-b2-verify.mjs 运行时冒烟（product 页浅深双版，0 报错，hydration 通过）

验证：type-check 0 错 / lint 0 错(127 既有 warnings) / 单测 129 套件 1628 通过

src/app/(marketing)/services/service-detail-content-v4.tsx

@@ -2,10 +2,10 @@
 
 import { motion } from 'framer-motion';
 import { CTAButton } from '@/components/ui/cta-button';
-import { ArrowUpRight, CheckCircle2, Zap, Clock, Users, Award, TrendingUp, Shield } from 'lucide-react';
+import { CheckCircle2, Zap, Clock, Users, Award, TrendingUp, Shield } from 'lucide-react';
 import type { LucideIcon } from 'lucide-react';
-import type { Service, CaseStudy } from '@/lib/constants/services';
-import { L3EmptyFallback } from '@/components/detail';
+import type { Service } from '@/lib/constants/services';
+import { L3EmptyFallback, CaseStudiesSection } from '@/components/detail';
 
 const EASE_OUT = [0.22, 1, 0.36, 1] as const;
 
@@ -249,65 +249,9 @@ function ProcessSection({ service }: { service: Service }) {
   );
 }
 
-function CaseStudiesSection({ caseStudies = [] }: { caseStudies?: CaseStudy[] }) {
-  if (caseStudies.length === 0) return null;
-
-  return (
-    <section id="cases" className="relative py-20 sm:py-28 md:py-36 lg:py-44 overflow-hidden bg-bg-primary">
-      <div className="max-w-container mx-auto px-4 sm:px-6 lg:px-10">
-        <motion.div
-          initial={{ opacity: 0, y: 30 }}
-          whileInView={{ opacity: 1, y: 0 }}
-          viewport={{ once: true, margin: '-80px' }}
-          transition={{ duration: 0.8, ease: EASE_OUT }}
-          className="max-w-3xl mb-16 sm:mb-20 md:mb-24"
-        >
-          <h2 className="text-3xl sm:text-4xl md:text-5xl lg:text-6xl font-extrabold text-ink tracking-tight leading-[0.95]">
-            真实案例，<br className="sm:hidden" />可衡量的成果
-          </h2>
-        </motion.div>
-
-        <div className="grid md:grid-cols-2 gap-px bg-border-primary">
-          {caseStudies.slice(0, 4).map((cs, i) => (
-            <motion.a
-              key={i}
-              href={`/cases/${cs.client.toLowerCase().replace(/\s+/g, '-')}`}
-              initial={{ opacity: 0, y: 20 }}
-              whileInView={{ opacity: 1, y: 0 }}
-              viewport={{ once: true, margin: '-60px' }}
-              transition={{ duration: 0.6, delay: i * 0.08, ease: EASE_OUT }}
-              className="group relative block p-8 sm:p-10 transition-all duration-500 hover:bg-bg-secondary hover:shadow-lg hover:-translate-y-1 bg-bg-primary border border-transparent hover:border-border-primary"
-            >
-
-              <div className="relative z-10">
-                <div className="flex items-center gap-3 mb-5">
-                  <span className="text-xs font-medium text-brand">
-                    {cs.industry}
-                  </span>
-                  <span className="text-border-primary">•</span>
-                  <span className="text-sm text-text-secondary">{cs.client}</span>
-                </div>
-
-                <h3 className="text-xl sm:text-2xl font-bold mb-6 text-ink leading-tight group-hover:text-brand transition-colors duration-300">
-                  {cs.challenge.slice(0, 30)}
-                </h3>
-
-                <p className="text-sm leading-relaxed mb-6 text-text-secondary">
-                  {cs.solution}
-                </p>
-
-                <div className="inline-flex items-center gap-2 text-sm font-semibold text-text-secondary group-hover:text-brand transition-colors duration-300">
-                  <span>查看详情</span>
-                  <ArrowUpRight className="w-4 h-4 group-hover:translate-x-0.5 group-hover:-translate-y-0.5 transition-transform duration-300" />
-                </div>
-              </div>
-            </motion.a>
-          ))}
-        </div>
-      </div>
-    </section>
-  );
-}
+// L3 信任层「客户案例」已合并至共享组件（@/components/detail）。
+// 原本地实现为异类：卡片 motion.a 链接 /cases/<slug>（依赖尚不存在的案例数据，链向 404
+// 违反零编造）+ 动效 0.8s 违规。统一后卡片不带链接，id="cases" 保留供 hero CTA 锚点。
 
 function CTASection() {
   return (
@@ -319,7 +263,7 @@ function CTASection() {
           initial={{ opacity: 0, y: 30 }}
           whileInView={{ opacity: 1, y: 0 }}
           viewport={{ once: true, margin: '-80px' }}
-          transition={{ duration: 0.8, ease: EASE_OUT }}
+          transition={{ duration: 0.7, ease: EASE_OUT }}
           className="max-w-3xl"
         >
           <h2 className="text-3xl sm:text-4xl md:text-5xl lg:text-6xl font-extrabold text-ink tracking-tight leading-[0.95] mb-8">
@@ -352,7 +296,7 @@ export default function ServiceDetailContentV4({ service }: { service: Service }
       <FeaturesSection service={service} />
       <ProcessSection service={service} />
       <L3EmptyFallback caseStudies={service.caseStudies} />
-      <CaseStudiesSection caseStudies={service.caseStudies} />
+      <CaseStudiesSection caseStudies={service.caseStudies} id="cases" heading="真实案例，可衡量的成果" />
       <CTASection />
     </main>
   );