feat(store): add shared Zustand store package with counter example

- Create packages/store with @multica/store package
- Add zustand to pnpm catalog for version consistency
- Add counter store as cross-platform state example
- Integrate counter into ComponentExample for verification
- Add tsconfig path mappings for web and desktop
- Add @multica/store to Next.js transpilePackages
- Add @multica/store dependency to packages/ui

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/web/next.config.ts

@@ -1,7 +1,7 @@
 import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
-  transpilePackages: ["@multica/ui"],
+  transpilePackages: ["@multica/ui", "@multica/store"],
 };
 
 export default nextConfig;