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/src/hooks/use-media-query.ts

@@ -3,7 +3,6 @@
 import { useEffect, useState } from 'react';
 
 export function useMediaQuery(query: string): boolean {
-  // 1) Always default to `false`—this guarantees SSR and the very first client render match.
   const [matches, setMatches] = useState(false);
 
   useEffect(() => {
@@ -13,10 +12,8 @@ export function useMediaQuery(query: string): boolean {
 
     const mediaQueryList = window.matchMedia(query);
 
-    // 2) On mount, immediately set to the real match value (true or false).
     setMatches(mediaQueryList.matches);
 
-    // 3) Subscribe to changes.
     const listener = (event: MediaQueryListEvent) => {
       setMatches(event.matches);
     };