Refactor nav_entries_oob into composable shared macro with caller block

Replace the shared fallback template with a Jinja macro that each domain
(blog, events, market) can call with its own domain-specific nav items.

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

events/templates/_types/post/admin/_nav_entries_oob.html

@@ -0,0 +1,34 @@
+{# OOB swap for nav entries and calendars when toggling associations or editing calendars #}
+{% from 'macros/nav_entries.html' import nav_entries_oob %}
+
+{% set has_items = (associated_entries and associated_entries.entries) or calendars %}
+{% call nav_entries_oob(has_items) %}
+  {% if associated_entries and associated_entries.entries %}
+    {% for entry in associated_entries.entries %}
+      {% set _entry_path = '/' + post.slug + '/calendars/' + entry.calendar_slug + '/' + entry.start_at.year|string + '/' + entry.start_at.month|string + '/' + entry.start_at.day|string + '/entries/' + entry.id|string + '/' %}
+      <a
+        href="{{ events_url(_entry_path) }}"
+        class="{{styles.nav_button_less_pad}}">
+        <div class="w-8 h-8 rounded bg-stone-200 flex-shrink-0"></div>
+        <div class="flex-1 min-w-0">
+          <div class="font-medium truncate">{{ entry.name }}</div>
+          <div class="text-xs text-stone-600 truncate">
+            {{ entry.start_at.strftime('%b %d, %Y at %H:%M') }}
+            {% if entry.end_at %} – {{ entry.end_at.strftime('%H:%M') }}{% endif %}
+          </div>
+        </div>
+      </a>
+    {% endfor %}
+  {% endif %}
+  {% if calendars %}
+    {% for calendar in calendars %}
+      {% set local_href=events_url('/' + post.slug + '/calendars/' + calendar.slug + '/') %}
+      <a
+        href="{{ local_href }}"
+        class="{{styles.nav_button_less_pad}}">
+        <i class="fa fa-calendar" aria-hidden="true"></i>
+        <div>{{calendar.name}}</div>
+      </a>
+    {% endfor %}
+  {% endif %}
+{% endcall %}