Cms homepage shuffle papercuts (#17163)

* fix: allow new HomePage to be the parent of any other kind of page

* fix: pass fallback_ftl_files to prefer_cms for HomePage and AboutPage, remove duplicate home route from urls.py

* feat: improve copilot auto-review instructions to catch a gap in prefer_cms usage

* fix: make speccing fallback files for prefer_cms more robust

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* fix: avoid copilot meta instructions that seem to trip it up - make clear which copilot rules are canonical

---------

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: stevejalim

.github/copilot-instructions.md

@@ -6,7 +6,8 @@ Fetch the latest version of all the checklists mentioned on https://mozmeao.gith
 
 Read AGENTS.md for supplementary instructions.
 
-If a mirrored copy of these instructions exists at `custom-instructions/repo/.github/copilot-instructions.md`, keep it fully synchronized with this file and any referenced AGENTS.md guidance, including section renumbering and DB schema guidance, or remove it to avoid drift and inconsistent Copilot behavior.
+If a mirrored copy of these instructions exists at `custom-instructions/repo/.github/copilot-instructions.md`, keep it fully synchronized with this file and any referenced AGENTS.md guidance, including section renumbering and DB schema guidance, or remove it to avoid drift and inconsistent Copilot behavior. If the mirrored version is out of sync, use this version as the canonical source and overwrite the mirrored version.
+
 Try to use Conventional Comments to indicate the kind of feedback you are providing, and whether it's blocking or non-blocking.
 
 Also, confirm in a comment on the PR that you are using this custom instructions file, please.
@@ -59,6 +60,8 @@ Be particularly aware of CMS-backed content that is not richtext. Ensure it's es
 
 * If a new Snippet (a Django model decorated with @register_snippet) is added, add a reminder in a comment to ensure that the Editors have permission to see and edit the new Snippet. That permission is added manually via the Wagtail UI.
 
+* If a Django view is being decorated for the first time with the `prefer_cms()` decorator and there is no `fallback_ftl_files=` parameter being passed in to `prefer_cms()`, add a non-blocking comment questioning whether it should be present, because without it, the page will only show the locales available in the CMS in the footer links on the page
+
 ## 8. Database schema changes
 
 * We use Django migrations to manage database schema state and also sometimes to adjust data. Django migrations are the ONLY permissible way to change database schema.

bedrock/mozorg/models.py

@@ -440,7 +440,6 @@ class HomePage(AbstractBedrockCMSPage):
     """CMS-managed homepage for mozilla.org."""
 
     max_count = 1  # Ensure there's only one instance of this page
-    subpage_types = []  # This page type cannot have any children
     ftl_files = ["mozorg/home-m24"]
 
     content = StreamField(

bedrock/mozorg/urls.py

@@ -21,8 +21,8 @@
 from .util import page
 
 urlpatterns = [
-    path("", prefer_cms(views.HomeView.as_view()), name="mozorg.home"),
-    path("about/", prefer_cms(views.AboutView.as_view()), name="mozorg.about.index"),
+    path("", prefer_cms(views.HomeView.as_view(), fallback_ftl_files=views.HomeView.activation_files), name="mozorg.home"),
+    path("about/", prefer_cms(views.AboutView.as_view(), fallback_ftl_files=views.AboutView.activation_files), name="mozorg.about.index"),
     page("about/manifesto/", "mozorg/about/manifesto.html", ftl_files=["mozorg/about/manifesto"]),
     page("about/manifesto/details/", "mozorg/about/manifesto-details.html", ftl_files=["mozorg/about/manifesto"]),
     page("account/", "mozorg/account.html", ftl_files=["firefox/accounts"]),

bedrock/urls.py

@@ -15,8 +15,6 @@
 from bedrock.base import views as base_views
 from bedrock.base.i18n import bedrock_i18n_patterns
 from bedrock.cms import wagtail_urls
-from bedrock.cms.decorators import prefer_cms
-from bedrock.mozorg import views as mozorg_views
 
 # The default django 404 and 500 handler doesn't run the ContextProcessors,
 # which breaks the base template page. So we replace them with views that do!
@@ -28,7 +26,6 @@
 # Paths that should have a locale prefix
 urlpatterns = bedrock_i18n_patterns(
     # Main pages
-    path("", prefer_cms(mozorg_views.HomeView.as_view()), name="mozorg.home"),
     path("foundation/", include("bedrock.foundation.urls")),
     path("about/legal/", include("bedrock.legal.urls")),
     path("press/", include("bedrock.press.urls")),