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/lib/constants/cases.ts

@@ -29,7 +29,7 @@ export interface CaseItem {
   /** 成果数据 */
   results: CaseResult[];
   /** 客户证言 */
-  testimonial: CaseTestimonial;
+  testimonial?: CaseTestimonial;
   tags: string[];
   image: string;
   /** 合作时长 */