Fixes #21173: Fix plugin menu registration order timing issue (#21248)

* Fixes #21173: Fix plugin menu registration order timing issue

- Converted static MENUS list to dynamic get_menus() function
- Ensures plugin menus are built at request time after all plugins complete ready()
- Fixes issue where only first few plugin menus appeared in navigation sidebar
- Updated navigation template tag to call get_menus() dynamically

* Fix ruff linting errors

- Add missing blank line before get_menus() function definition
- Remove trailing whitespace

* Add @cache decorator to get_menus() for performance optimization

Per reviewer feedback, the menu list is now cached since it doesn't change
without a Django restart. This eliminates redundant list building on each request.

---------

Co-authored-by: adionit7 <adionit7@users.noreply.github.com>

netbox/netbox/navigation/menu.py

@@ -1,3 +1,5 @@
+from functools import cache
+
 from django.utils.translation import gettext_lazy as _
 
 from netbox.registry import registry
@@ -501,7 +503,15 @@ ADMIN_MENU = Menu(
     ),
 )
 
-MENUS = [
+
+@cache
+def get_menus():
+    """
+    Dynamically build and return the list of navigation menus.
+    This ensures plugin menus registered during app initialization are included.
+    The result is cached since menus don't change without a Django restart.
+    """
+    menus = [
         ORGANIZATION_MENU,
         RACKS_MENU,
         DEVICES_MENU,
@@ -515,15 +525,14 @@ MENUS = [
         PROVISIONING_MENU,
         CUSTOMIZATION_MENU,
         OPERATIONS_MENU,
-]
+    ]
 
-# Add top-level plugin menus
-for menu in registry['plugins']['menus']:
-    MENUS.append(menu)
-
-# Add the default "plugins" menu
-if registry['plugins']['menu_items']:
+    # Add top-level plugin menus
+    for menu in registry['plugins']['menus']:
+        menus.append(menu)
 
+    # Add the default "plugins" menu
+    if registry['plugins']['menu_items']:
         # Build the default plugins menu
         groups = [
             MenuGroup(label=label, items=items)
@@ -534,7 +543,9 @@ if registry['plugins']['menu_items']:
             icon_class="mdi mdi-puzzle",
             groups=groups
         )
-    MENUS.append(plugins_menu)
+        menus.append(plugins_menu)
 
-# Add the admin menu last
-MENUS.append(ADMIN_MENU)
+    # Add the admin menu last
+    menus.append(ADMIN_MENU)
+
+    return menus

netbox/utilities/templatetags/navigation.py

@@ -1,6 +1,6 @@
 from django import template
 
-from netbox.navigation.menu import MENUS
+from netbox.navigation.menu import get_menus
 
 __all__ = (
     'nav',
@@ -19,7 +19,7 @@ def nav(context):
     nav_items = []
 
     # Construct the navigation menu based upon the current user's permissions
-    for menu in MENUS:
+    for menu in get_menus():
         groups = []
         for group in menu.groups:
             items = []