Fix: update local _nav.html to use widget-driven nav

The blog app's local templates/_types/post/_nav.html was shadowing
the shared version due to ChoiceLoader priority. Updated local copy
to use container_nav_widgets while keeping the blog-specific admin
cog link. Removed debug logging from context processor.

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

templates/_types/post/_nav.html

@@ -1,6 +1,6 @@
 {% import 'macros/links.html' as links %}
-    {# Associated Entries and Calendars - vertical on mobile, horizontal with arrows on desktop #}
-    {% if (associated_entries and associated_entries.entries) or calendars or markets %}
+    {# Widget-driven container nav — entries, calendars, markets #}
+    {% if container_nav_widgets %}
       <div class="flex flex-col sm:flex-row sm:items-center gap-2 border-r border-stone-200 mr-2 sm:max-w-2xl"
            id="entries-calendars-nav-wrapper">
         {% include '_types/post/admin/_nav_entries.html' %}
@@ -9,7 +9,6 @@
 
     {# Admin link #}
   {% if post and has_access('blog.post.admin.admin') %}
-      {% import 'macros/links.html' as links %}
       {% call links.link(url_for('blog.post.admin.admin', slug=post.slug), hx_select_search, select_colours, True, aclass=styles.nav_button) %}
         <i class="fa fa-cog" aria-hidden="true"></i>
       {% endcall %}