Initial federation app — ActivityPub server for Rose-Ash

Phase 0+1 of AP integration. New 5th Quart microservice:

Blueprints:
- wellknown: WebFinger, NodeInfo 2.0, host-meta
- actors: AP actor profiles (JSON-LD + HTML), outbox, inbox, followers
- identity: username selection flow (creates ActorProfile + RSA keypair)
- auth: magic link login/logout (ported from blog, self-contained)

Services:
- Registers SqlFederationService (real impl) for federation domain
- Registers real impls for blog, calendar, market, cart
- All cross-domain via shared service contracts

Templates:
- Actor profiles, username selection, platform home
- Auth login/check-email (ported from blog)

Infrastructure:
- Dockerfile + entrypoint.sh (matches other apps)
- CI/CD via Gitea Actions
- shared/ as git submodule

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

templates/auth/check_email.html

@@ -0,0 +1,18 @@
+{% extends "federation/base.html" %}
+{% block title %}Check your email — Rose Ash{% endblock %}
+{% block content %}
+<div class="py-8 max-w-md mx-auto text-center">
+  <h1 class="text-2xl font-bold mb-4">Check your email</h1>
+  <p class="text-stone-600 mb-2">
+    We sent a sign-in link to <strong>{{ email }}</strong>.
+  </p>
+  <p class="text-stone-500 text-sm">
+    Click the link in the email to sign in. The link expires in 15 minutes.
+  </p>
+  {% if email_error %}
+    <div class="bg-yellow-50 border border-yellow-200 text-yellow-700 p-3 rounded mt-4">
+      {{ email_error }}
+    </div>
+  {% endif %}
+</div>
+{% endblock %}