feat(detail): Layer 3 信任层空数据兜底骨架（L3SignalsSlot + L3EmptyFallback + EarlyAccessNotice）

- 新增 L3SignalsSlot：4 类可验证替代信号卡（方法论/团队/历程/服务承诺），
  服务承诺卡 disabled 占位待业务确认；零编造约束下替代真实案例/认证
- 新增 EarlyAccessNotice：首批客户共创状态条（单一真源 company.ts EARLY_ACCESS）
- 新增 L3EmptyFallback：caseStudies/certifications/dataProofs 三者全空时渲染兜底，
  任一非空 return null 保留本地真实 section 视觉
- 接入 5 处详情页：solution v3 / service v4 / product v3 / erp-upgrade-v3 / standalone/[id]
- 修复 StaggerReveal 网格布局：grid 类须挂在 StaggerReveal 自身（否则卡片堆单列）
- 更新 solution 测试至新行为（空数据→兜底渲染）+ 补 lucide 图标 mock
- 修复 header.test.tsx 双 logo 断言（2593599 遗留）
- 新增 scripts/audit/l3-fallback-verify.mjs 运行时验证（浅/深双版 PASS）
  注：必须用 localhost 而非 127.0.0.1 —— Next dev allowedDevOrigins 默认白名单
  不含 127.0.0.1，chunk 请求带该 Origin 被 403 → hydration 不发生 → 动画全冻结

验证：type-check 0 错 · lint 0 错(127 既有 warnings) · 单测 129 套件/1628 通过 ·
L3 兜底浅深双版渲染截图 PASS

src/app/(marketing)/products/erp-upgrade-v3/page.tsx

@@ -6,6 +6,7 @@ import { DetailHero } from '@/components/detail/detail-hero';
 import { ProductValueSection } from '@/components/detail/detail-product-value';
 import { DetailTrustSection } from '@/components/detail/detail-trust-section';
 import { DetailCTASection } from '@/components/detail/detail-cta-section';
+import { L3EmptyFallback } from '@/components/detail';
 import type { HeroTheme } from '@/lib/constants/hero-themes';
 import type { Product, CaseStudy, DataProof, Certification } from '@/lib/constants/products';
 
@@ -70,6 +71,7 @@ export default async function ERPUpgradeV3Page() {
 
       <ProductValueSection product={data as unknown as Product} />
 
+      <L3EmptyFallback caseStudies={caseStudies} dataProofs={dataProofs} certifications={certifications} />
       <DetailTrustSection
         caseStudies={caseStudies}
         dataProofs={dataProofs}

src/app/(marketing)/products/product-detail-content-v3.tsx

@@ -8,6 +8,7 @@ import { ArrowRight, Package, Check, Settings, Users, FileText, Cpu, Shield, Tre
 import { SectionLabel, EASE_OUT } from '@/components/ui/page-decoration';
 import type { Product } from '@/lib/constants/products';
 import { MethodologyFramework, TechStackShowcase, FAQSection, DataProofSection } from '@/components/content/sections';
+import { L3EmptyFallback } from '@/components/detail';
 
 const PRODUCT_ICONS: Record<string, React.ReactNode> = {
   '睿新ERP管理系统': <Package className="w-8 h-8" />,
@@ -453,6 +454,7 @@ export default function ProductDetailContentV3({ product }: ProductDetailContent
           categories={product.techStack}
         />
       )}
+      <L3EmptyFallback caseStudies={product.caseStudies} certifications={product.certifications} dataProofs={product.dataProofs} />
       {product.dataProofs && product.dataProofs.length > 0 && (
         <DataProofSection
           title="可衡量的成果"

src/app/(marketing)/products/standalone/[id]/client.tsx

@@ -5,6 +5,7 @@ import { CTAButton } from '@/components/ui/cta-button';
 import { DetailHero } from '@/components/detail/detail-hero';
 import { DetailTrustSection } from '@/components/detail/detail-trust-section';
 import { DetailCTASection } from '@/components/detail/detail-cta-section';
+import { L3EmptyFallback } from '@/components/detail';
 import { DetailSwipeNav } from '@/components/ui/detail-swipe-nav';
 import { motion } from 'framer-motion';
 import { CheckCircle2, Shield, Lock, Cpu, HardDrive, FileCheck, Gauge } from 'lucide-react';
@@ -257,6 +258,7 @@ export function StandaloneProductClient({ item }: StandaloneProductClientProps)
             </section>
           )}
 
+          <L3EmptyFallback caseStudies={caseStudies} dataProofs={dataProofs} certifications={certifications} />
           <DetailTrustSection
             caseStudies={caseStudies}
             dataProofs={dataProofs}

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

@@ -5,6 +5,7 @@ import { CTAButton } from '@/components/ui/cta-button';
 import { ArrowUpRight, 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';
 
 const EASE_OUT = [0.22, 1, 0.36, 1] as const;
 
@@ -350,6 +351,7 @@ export default function ServiceDetailContentV4({ service }: { service: Service }
       <OverviewSection service={service} />
       <FeaturesSection service={service} />
       <ProcessSection service={service} />
+      <L3EmptyFallback caseStudies={service.caseStudies} />
       <CaseStudiesSection caseStudies={service.caseStudies} />
       <CTASection />
     </main>

src/app/(marketing)/solutions/solution-detail-content-v3.test.tsx

@@ -63,6 +63,11 @@ jest.mock('lucide-react', () => {
     Route: mockIcon('route'),
     Shield: mockIcon('shield'),
     Truck: mockIcon('truck'),
+    // L3SignalsSlot（L3 空数据兜底，commit: L3 骨架）用到的图标
+    ArrowUpRight: mockIcon('arrow-up-right'),
+    Compass: mockIcon('compass'),
+    Milestone: mockIcon('milestone'),
+    ShieldCheck: mockIcon('shield-check'),
   };
 });
 
@@ -87,11 +92,24 @@ const baseSolution = {
 } as Solution;
 
 describe('SolutionDetailContentV3 - L3 信任层三档策略', () => {
-  it('does not render L3 sections when no case/certification data exists', () => {
+  it('renders L3 fallback (signals + early-access notice) when no case/certification data exists', () => {
+    // 修订方案 B'（2026-09-02）：空数据不再是「整段消失 = 信任真空」，
+    // 而是由 L3EmptyFallback 渲染 4 类替代信号卡 + 首批客户共创占位。
     render(<SolutionDetailContentV3 solution={baseSolution} />);
 
+    // 真实数据 section 仍不渲染
     expect(screen.queryByText('同行业落地案例')).not.toBeInTheDocument();
     expect(screen.queryByText('资质认证')).not.toBeInTheDocument();
+
+    // 兜底：信任锚点信号区 + 共创占位
+    expect(screen.getByText('在数据之外，我们用透明度建立信任')).toBeInTheDocument();
+    expect(screen.getByRole('link', { name: /交付方法论/ })).toHaveAttribute('href', '/methodology');
+    expect(screen.getByRole('link', { name: /团队资历/ })).toHaveAttribute('href', '/team');
+    expect(screen.getByRole('link', { name: /发展历程/ })).toHaveAttribute('href', '/about/brand');
+    // 服务承诺卡：disabled 占位，不可点击
+    expect(screen.getByText(/服务承诺/)).toBeInTheDocument();
+    expect(screen.getByText('待业务确认')).toBeInTheDocument();
+    expect(screen.getByText('首批客户共创中')).toBeInTheDocument();
   });
 
   it('renders case studies when data is available', () => {

src/app/(marketing)/solutions/solution-detail-content-v3.tsx

@@ -6,6 +6,7 @@ import { CTAButton } from '@/components/ui/cta-button';
 import { Factory, ShoppingCart, Heart, GraduationCap, Lightbulb, Settings, Users, TrendingUp, Package, BookOpen, MessageSquare, Calendar, Smartphone, Route, Shield, Truck } from 'lucide-react';import { SectionLabel, EASE_OUT } from '@/components/ui/page-decoration';
 import type { Solution } from '@/lib/constants/solutions';
 import type { Product } from '@/lib/constants/products';
+import { L3EmptyFallback } from '@/components/detail';
 
 const INDUSTRY_ICONS: Record<string, React.ReactNode> = {
   制造业: <Factory className="w-8 h-8" />,
@@ -514,6 +515,7 @@ export default function SolutionDetailContentV3({ solution, products = [] }: Sol
       <SolutionsSection solutions={solution.solutions} />
       <ValuePropositionSection valueProposition={solution.valueProposition} />
       <SuiteCombinationSection suiteCombination={solution.suiteCombination} products={products} />
+      <L3EmptyFallback caseStudies={solution.caseStudies} certifications={solution.certifications} />
       <CaseStudiesSection caseStudies={solution.caseStudies} />
       <CertificationsSection certifications={solution.certifications} />
       <CTASection solution={solution} />