Fix actors.profile → activitypub.actor_profile endpoint references

The AP blueprint was consolidated but 4 references to the old
'actors.profile' endpoint remained, causing BuildError on social pages.

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

templates/_types/social/header/_header.html

@@ -34,7 +34,7 @@
             <span hx-get="{{ url_for('social.notification_count') }}" hx-trigger="load, every 30s" hx-swap="innerHTML"
                   class="absolute -top-2 -right-3 text-xs bg-red-500 text-white rounded-full px-1 empty:hidden"></span>
           </a>
-          <a href="{{ url_for('actors.profile', username=actor.preferred_username) }}"
+          <a href="{{ url_for('activitypub.actor_profile', username=actor.preferred_username) }}"
              class="px-2 py-1 rounded hover:bg-stone-200">
             @{{ actor.preferred_username }}
           </a>

templates/federation/account.html

@@ -9,7 +9,7 @@
     {% if actor %}
       <p class="mt-2"><strong>Username:</strong> @{{ actor.preferred_username }}</p>
       <p class="mt-1">
-        <a href="{{ url_for('actors.profile', username=actor.preferred_username) }}"
+        <a href="{{ url_for('activitypub.actor_profile', username=actor.preferred_username) }}"
            class="text-blue-600 hover:underline">
           View profile
         </a>