chore: upgrade dependencies, restructure shared libs, and fix UI

- Upgrade Nx 22.1.1 → 22.6.3 and all patch/minor dependencies
- Restructure shared libs: move business logic from utils to service
- Consolidate shadcn-ui into ui lib with atomic design pattern
- Fix container centering for landing app (Tailwind v4 compatibility)
- Fix button styling by updating @source directive in globals.css
- Fix SiCss3 → SiCss rename in react-icons 5.6
- Fix duplicate useSession export conflict
- Remove dead code, comments, and unused files

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/landing/tsconfig.json

@@ -23,10 +23,15 @@
     ],
     "baseUrl": ".",
     "paths": {
-      "@components": ["../../libs/shadcn-ui/src/atoms/index.ts"],
-      "@utils": ["../../libs/shadcn-ui/src/lib/index.ts"],
+      "@components": ["../../libs/ui/src/atoms/index.ts"],
+      "@utils": ["../../libs/utils/src/tailwind-merge/index.ts"],
       "@schemas": ["../../libs/service/src/schemas/index.ts"],
-      "@/*": ["src/*"]
+      "@/*": ["src/*"],
+      "@imphnen-frontend-service/service": ["../../libs/service/src/index.ts"],
+      "@imphnen-frontend-service/ui/atoms": ["../../libs/ui/src/atoms/index.ts"],
+      "@imphnen-frontend-service/ui/molecules": ["../../libs/ui/src/molecules/index.ts"],
+      "@imphnen-frontend-service/ui/organisms": ["../../libs/ui/src/organisms/index.ts"],
+      "@imphnen-frontend-service/utils": ["../../libs/utils/src/index.ts"]
     }
   },
   "include": [