Integrate federation app with shared menu/header system

Replace standalone base.html with the shared _types/root layout.
Social pages get a second nav row via _types/social/index.html.
Root / becomes a blank page with shared chrome. Auth pages use
the shared layout without the social nav bar.

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

templates/auth/check_email.html

@@ -1,4 +1,5 @@
-{% extends "federation/base.html" %}
+{% extends "_types/root/_index.html" %}
+{% block meta %}{% endblock %}
 {% block title %}Check your email — Rose Ash{% endblock %}
 {% block content %}
 <div class="py-8 max-w-md mx-auto text-center">

templates/auth/login.html

@@ -1,4 +1,5 @@
-{% extends "federation/base.html" %}
+{% extends "_types/root/_index.html" %}
+{% block meta %}{% endblock %}
 {% block title %}Login — Rose Ash{% endblock %}
 {% block content %}
 <div class="py-8 max-w-md mx-auto">