feat(analytics): enhance Google Analytics with privacy compliance and comprehensive tracking

- Add automatic route change tracking for SPA navigation
- Implement Cookie consent banner for GDPR compliance
- Add performance tracking (LCP, FID, CLS Web Vitals)
- Add outbound link click tracking
- Integrate contact form submission tracking with conversion events
- Add CTA button click tracking in hero section
- Integrate error tracking in ErrorBoundary component
- Extend analytics utility library with 15+ tracking functions
- Configure IP anonymization and privacy settings
- Remove unused test files and deployment scripts
- Update case studies to include only specified cases
- Fix mobile navigation active state issues
- Fix lint errors in test files and components

BREAKING CHANGE: Google Analytics now requires user consent before tracking

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

@@ -48,7 +48,7 @@ interface CaseItem {
   /** 成果数据 */
   results: CaseResult[];
   /** 客户证言 */
-  testimonial: CaseTestimonial;
+  testimonial?: CaseTestimonial;
   /** 合作时长 */
   duration: string;
 }
@@ -79,7 +79,7 @@ export function CaseDetailClient({ caseItem }: CaseDetailClientProps) {
   }, []);
 
   return (
-    <main className="min-h-screen bg-white">
+    <div className="min-h-screen bg-white">
       <div className="relative overflow-hidden bg-gradient-to-b from-[#FAFAFA] to-white">
         <div className="container-wide relative z-10 pt-32 pb-20">
           <BackButton />
@@ -281,6 +281,6 @@ export function CaseDetailClient({ caseItem }: CaseDetailClientProps) {
           </div>
         </div>
       </div>
-    </main>
+    </div>
   );
 }