Add post-login welcome and friendly how-it-works guide

frontend/app/ui/ApplicationChrome.tsx

@@ -10,7 +10,7 @@ import WorkspaceNavigation from './WorkspaceNavigation'
 
 export default function ApplicationChrome() {
   const pathname = usePathname()
-  if (['/coming-soon', '/login', '/forgot-password', '/reset-password', '/signup'].includes(pathname)) return null
+  if (['/welcome', '/coming-soon', '/login', '/forgot-password', '/reset-password', '/signup'].includes(pathname)) return null
   return <>
     <header className="header">
       <div className="header-left"><a className="brand-link" href="/"><BrandingLogo className="brand-logo brand-logo--header" /><div className="brand-stack"><div className="brand">Magent</div><div className="tagline">GrizzlyFlix media operations</div></div></a></div>

frontend/app/ui/HeaderIdentity.tsx

@@ -93,6 +93,8 @@ export default function HeaderIdentity() {
               {viewAsUser ? <span>Previewing user view</span> : null}
             </div>
             <div className="signed-in-actions">
+              <a href="/welcome" onClick={() => setOpen(false)}>Welcome page</a>
+              <a href="/how-it-works" onClick={() => setOpen(false)}>How it works</a>
               <a href="/profile" onClick={() => setOpen(false)}>
                 My profile
               </a>