feat(wagtail): add home app with HomePage model and auto-run makemigrations

- Add home app template (models.py, apps.py, template, empty migrations/)
  with HomePage(Page) subclass matching the wagtail start pattern
- Register home app in WAGTAIL_INSTALLED_APPS so it's enabled by --wagtail
- Update _setup_wagtail_initial_data() to create a HomePage instance instead
  of a generic Page, so the Wagtail admin shows a real page type
- Add makemigrations step to run_project() before migrate when Wagtail is
  installed — populates MIGRATION_MODULES-redirected packages on first run,
  no-op on subsequent runs
- Update wagtail-support.rst with Home App section and makemigrations note

Author: aclark4life

docs/design/wagtail-support.rst

@@ -23,8 +23,25 @@ Wagtail ships with its own migration files that include SQL-style assumptions in
        # ... one entry per Wagtail app
    }
 
-Run ``manage.py makemigrations`` after configuring this to generate MongoDB-compatible migration files for each app. Django will use these in-project migrations instead of the ones bundled with Wagtail.
+``dbx project run`` automatically runs ``manage.py makemigrations`` before ``migrate`` whenever Wagtail is installed. On first run this populates the empty in-project packages with MongoDB-compatible migration files; on subsequent runs it is a no-op.
 
+Home App
+---------
+
+**Decision: ship a ``home`` app with a ``HomePage(Page)`` model**
+
+The template includes a ``home`` app (mirroring what ``wagtail start`` generates) so the site has a concrete starting point for building out page types:
+
+.. code-block:: python
+
+   # home/models.py
+   class HomePage(Page):
+       body = RichTextField(blank=True)
+       content_panels = Page.content_panels + [FieldPanel("body")]
+
+``dbx project run`` creates the Wagtail root page and a ``HomePage`` instance programmatically (not via a data migration), then points the default ``Site`` at that home page. The Wagtail admin is immediately usable on first run.
+
+To add more page types, subclass ``Page`` in a new app or in ``home/models.py`` and run ``manage.py makemigrations``.
 
 Custom App Configurations
 --------------------------

src/dbx_python_cli/commands/project.py

@@ -1089,11 +1089,12 @@ def _setup_wagtail_initial_data(
         "        from django.conf import settings as _s",
         "        from django.contrib.contenttypes.models import ContentType",
         "        from wagtail.models import Locale, Site",
+        f"        from {proj.name}.home.models import HomePage",
         "        lang = (getattr(_s, 'LANGUAGE_CODE', 'en') or 'en').split('-')[0][:2]",
         "        locale, _ = Locale.objects.get_or_create(language_code=lang)",
         "        page_ct, _ = ContentType.objects.get_or_create(app_label='wagtailcore', model='page')",
         "        root = Page.add_root(title='Root', slug='root', content_type=page_ct, locale=locale)",
-        "        home = root.add_child(instance=Page(title='Home', slug='home', content_type=page_ct, locale=locale))",
+        "        home = root.add_child(instance=HomePage(title='Home', slug='home', locale=locale))",
         "        print('wagtail_root_created')",
         "        if not Site.objects.exists():",
         "            Site.objects.create(hostname='localhost', root_page=home, is_default_site=True)",
@@ -1386,11 +1387,33 @@ def run_project(
     venv_bin = str(Path(python_path).parent)
     env["PATH"] = f"{venv_bin}{os.pathsep}{env.get('PATH', '')}"
 
-    # Run migrations before starting server
-    typer.echo(f"🗄️  Running migrations for project '{proj.name}'")
     migrate_env = setup_django_command_env(
         proj, ctx, settings=settings, include_dyld_fallback=False
     )
+
+    # Generate migrations for Wagtail apps (MIGRATION_MODULES redirects them to
+    # in-project packages; makemigrations populates those packages on first run
+    # and is a no-op on subsequent runs when nothing has changed).
+    has_wagtail = subprocess.run(
+        [python_path, "-c", "import wagtail"],
+        cwd=proj.project_path,
+        env=migrate_env,
+        check=False,
+        capture_output=True,
+    )
+    if has_wagtail.returncode == 0:
+        typer.echo("⚙️  Generating Wagtail migrations...")
+        subprocess.run(
+            [python_path, "-m", "django", "makemigrations"],
+            cwd=proj.project_path,
+            env=migrate_env,
+            check=False,
+            capture_output=not verbose,
+            text=True,
+        )
+
+    # Run migrations before starting server
+    typer.echo(f"🗄️  Running migrations for project '{proj.name}'")
     result = subprocess.run(
         [python_path, "-m", "django", "migrate"],
         cwd=proj.project_path,

src/dbx_python_cli/templates/project_template/project_name/home/__init__.py

@@ -0,0 +1,11 @@
+from django.apps import AppConfig
+from django.conf import settings
+
+
+class HomeConfig(AppConfig):
+    name = "{{ project_name }}.home"
+    verbose_name = "Home"
+
+    @property
+    def default_auto_field(self):
+        return getattr(settings, "DEFAULT_AUTO_FIELD", "django.db.models.BigAutoField")

src/dbx_python_cli/templates/project_template/project_name/home/apps.py

@@ -0,0 +1,14 @@
+from wagtail.fields import RichTextField
+from wagtail.models import Page
+from wagtail.admin.panels import FieldPanel
+
+
+class HomePage(Page):
+    body = RichTextField(blank=True)
+
+    content_panels = Page.content_panels + [
+        FieldPanel("body"),
+    ]
+
+    class Meta:
+        verbose_name = "Home page"

src/dbx_python_cli/templates/project_template/project_name/home/migrations/__init__.py

@@ -0,0 +1,11 @@
+{% extends "base.html" %}
+{% load wagtailcore_tags %}
+
+{% block content %}
+<div class="home-page">
+    <h1>{{ page.title }}</h1>
+    {% if page.body %}
+    <div class="body">{{ page.body|richtext }}</div>
+    {% endif %}
+</div>
+{% endblock %}

src/dbx_python_cli/templates/project_template/project_name/home/models.py

@@ -24,6 +24,7 @@
     "wagtail.sites",
     "modelcluster",
     "{{ project_name }}.settings.apps.wagtail.CustomTaggitConfig",
+    "{{ project_name }}.home",
 ]
 
 WAGTAIL_MIDDLEWARE = [