feat: downgrade tech stack to stable versions and integrate GA4 error monitoring

- Downgrade Next.js 16→14.2, React 19→18.3, Tailwind 4→3.4
- Add comprehensive GA4 error monitoring system
- Create Jenkins CI/CD pipeline with quality gates
- Fix build issues: ESLint, SWC conflict, config format
- Add documentation for deployment and error tracking

src/app/globals.css

@@ -1,11 +1,6 @@
-@import "tailwindcss";
-
-@theme inline {
-  --font-sans: var(--font-noto-sans-sc), var(--font-geist-sans), -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
-  --font-mono: var(--font-geist-mono);
-  --font-chinese: var(--font-noto-sans-sc), sans-serif;
-  --font-calligraphy: var(--font-ma-shan-zheng), 'ZCOOL XiaoWei', 'STKaiti', 'KaiTi', serif;
-}
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
 
 :root {
   --color-primary: #1C1C1C;