feat: implement PageLoader component and register maritime loader as the default theme loader

libs/auth/src/lib/components/AuthBootstrap.tsx

@@ -1,5 +1,6 @@
 import { useEffect, useState, type ReactNode } from 'react';
 import { useDispatch } from 'react-redux';
+import { PageLoader } from '@ema-platform/ui';
 import { authStorage } from '../utils/auth-storage';
 import { hydrateAuth, logout, setUser } from '../store/auth.slice';
 import type { AuthUser } from '../types/auth.types';
@@ -70,7 +71,7 @@ export function AuthBootstrap({ children }: { children: ReactNode }) {
 
   // Rendering the router before the session resolves would let the guards
   // redirect based on a state that is about to change.
-  if (!ready) return null;
+  if (!ready) return <PageLoader />;
 
   return <>{children}</>;
 }