Add glue layer support: MenuNode templates, factory registration, migration

- Templates: item.post.X → item.X (MenuNode has label/slug/feature_image directly)
- factory.py: add glue.models to import loop + register_glue_handlers() at startup
- alembic env.py: add glue.models to import loop
- New migration: container_relations + menu_nodes tables with backfill from existing data

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

browser/templates/_types/menu_items/_form.html

@@ -12,21 +12,21 @@
   </div>
 
   {# Hidden field for selected post ID - outside form for JS access #}
-  <input type="hidden" name="post_id" id="selected-post-id" value="{{ menu_item.post_id if menu_item else '' }}" />
+  <input type="hidden" name="post_id" id="selected-post-id" value="{{ menu_item.container_id if menu_item else '' }}" />
 
   {# Selected page display #}
   {% if menu_item %}
     <div id="selected-page-display" class="mb-3 p-3 bg-stone-50 rounded flex items-center gap-3">
-      {% if menu_item.post.feature_image %}
-        <img src="{{ menu_item.post.feature_image }}"
-             alt="{{ menu_item.post.title }}"
+      {% if menu_item.feature_image %}
+        <img src="{{ menu_item.feature_image }}"
+             alt="{{ menu_item.label }}"
              class="w-10 h-10 rounded-full object-cover" />
       {% else %}
         <div class="w-10 h-10 rounded-full bg-stone-200"></div>
       {% endif %}
       <div class="flex-1">
-        <div class="font-medium">{{ menu_item.post.title }}</div>
-        <div class="text-xs text-stone-500">{{ menu_item.post.slug }}</div>
+        <div class="font-medium">{{ menu_item.label }}</div>
+        <div class="text-xs text-stone-500">{{ menu_item.slug }}</div>
       </div>
     </div>
   {% else %}

browser/templates/_types/menu_items/_list.html

@@ -9,9 +9,9 @@
           </div>
 
           {# Page image #}
-          {% if item.post.feature_image %}
-            <img src="{{ item.post.feature_image }}"
-                 alt="{{ item.post.title }}"
+          {% if item.feature_image %}
+            <img src="{{ item.feature_image }}"
+                 alt="{{ item.label }}"
                  class="w-12 h-12 rounded-full object-cover flex-shrink-0" />
           {% else %}
             <div class="w-12 h-12 rounded-full bg-stone-200 flex-shrink-0"></div>
@@ -19,8 +19,8 @@
 
           {# Page title #}
           <div class="flex-1 min-w-0">
-            <div class="font-medium truncate">{{ item.post.title }}</div>
-            <div class="text-xs text-stone-500 truncate">{{ item.post.slug }}</div>
+            <div class="font-medium truncate">{{ item.label }}</div>
+            <div class="text-xs text-stone-500 truncate">{{ item.slug }}</div>
           </div>
 
           {# Sort order #}
@@ -42,7 +42,7 @@
               type="button"
               data-confirm
               data-confirm-title="Delete menu item?"
-              data-confirm-text="Remove {{ item.post.title }} from the menu?"
+              data-confirm-text="Remove {{ item.label }} from the menu?"
               data-confirm-icon="warning"
               data-confirm-confirm-text="Yes, delete"
               data-confirm-cancel-text="Cancel"

browser/templates/_types/menu_items/_nav_oob.html

@@ -4,11 +4,11 @@
      hx-swap-oob="outerHTML">
   {% from 'macros/scrolling_menu.html' import scrolling_menu with context %}
   {% call(item) scrolling_menu('menu-items-container', menu_items) %}
-    {% set _href = _app_slugs.get(item.post.slug, coop_url('/' + item.post.slug + '/')) %}
+    {% set _href = _app_slugs.get(item.slug, coop_url('/' + item.slug + '/')) %}
     <a
       href="{{ _href }}"
-      {% if item.post.slug not in _app_slugs %}
-        hx-get="/{{ item.post.slug }}/"
+      {% if item.slug not in _app_slugs %}
+        hx-get="/{{ item.slug }}/"
         hx-target="#main-panel"
         hx-select="{{ hx_select_search }}"
         hx-swap="outerHTML"
@@ -16,14 +16,14 @@
       {% endif %}
       class="{{styles.nav_button}}"
     >
-      {% if item.post.feature_image %}
-        <img src="{{ item.post.feature_image }}"
-             alt="{{ item.post.title }}"
+      {% if item.feature_image %}
+        <img src="{{ item.feature_image }}"
+             alt="{{ item.label }}"
              class="w-8 h-8 rounded-full object-cover flex-shrink-0" />
       {% else %}
         <div class="w-8 h-8 rounded-full bg-stone-200 flex-shrink-0"></div>
       {% endif %}
-      <span>{{ item.post.title }}</span>
+      <span>{{ item.label }}</span>
     </a>
   {% endcall %}
 </div>

browser/templates/_types/root/_nav.html

@@ -3,19 +3,19 @@
      id="menu-items-nav-wrapper">
   {% from 'macros/scrolling_menu.html' import scrolling_menu with context %}
   {% call(item) scrolling_menu('menu-items-container', menu_items) %}
-    {% set _href = _app_slugs.get(item.post.slug, coop_url('/' + item.post.slug + '/')) %}
+    {% set _href = _app_slugs.get(item.slug, coop_url('/' + item.slug + '/')) %}
     <a
       href="{{ _href }}"
       class="{{styles.nav_button_less_pad}}"
     >
-      {% if item.post.feature_image %}
-        <img src="{{ item.post.feature_image }}"
-             alt="{{ item.post.title }}"
+      {% if item.feature_image %}
+        <img src="{{ item.feature_image }}"
+             alt="{{ item.label }}"
              class="w-8 h-8 rounded-full object-cover flex-shrink-0" />
       {% else %}
         <div class="w-8 h-8 rounded-full bg-stone-200 flex-shrink-0"></div>
       {% endif %}
-      <span>{{ item.post.title }}</span>
+      <span>{{ item.label }}</span>
     </a>
   {% endcall %}
 </div>