Add test utilities and state machine diagrams for FSM models

- Introduced reusable test utilities in `backend/tests/utils` for FSM transitions, HTMX interactions, and common scenarios.
- Added factory functions for creating test submissions, parks, rides, and photo submissions.
- Implemented assertion helpers for verifying state changes, toast notifications, and transition logs.
- Created comprehensive state machine diagrams for all FSM-enabled models in `docs/STATE_DIAGRAMS.md`, detailing states, transitions, and guard conditions.

backend/apps/rides/park_urls.py

@@ -9,6 +9,8 @@ urlpatterns = [
     path("create/", views.RideCreateView.as_view(), name="ride_create"),
     # Park-specific detail views
     path("<slug:ride_slug>/", views.RideDetailView.as_view(), name="ride_detail"),
+    path("<slug:ride_slug>/status-actions/", views.ride_status_actions, name="ride_status_actions"),
+    path("<slug:ride_slug>/header-badge/", views.ride_header_badge, name="ride_header_badge"),
     path(
         "<slug:ride_slug>/update/",
         views.RideUpdateView.as_view(),

backend/apps/rides/urls.py

@@ -1,5 +1,6 @@
 from django.urls import path
 from . import views
+from apps.core.views.views import FSMTransitionView
 
 app_name = "rides"
 
@@ -83,4 +84,12 @@ urlpatterns = [
         views.RideUpdateView.as_view(),
         name="ride_update",
     ),
+    # FSM transition endpoint for rides
+    # URL: /rides/<ride_slug>/transition/<transition_name>/
+    path(
+        "<slug:slug>/transition/<str:transition_name>/",
+        FSMTransitionView.as_view(),
+        {"app_label": "rides", "model_name": "ride"},
+        name="ride_transition",
+    ),
 ]

backend/apps/rides/views.py

@@ -35,6 +35,33 @@ def show_coaster_fields(request: HttpRequest) -> HttpResponse:
     return render(request, "rides/partials/coaster_fields.html")
 
 
+def ride_status_actions(request: HttpRequest, park_slug: str, ride_slug: str) -> HttpResponse:
+    """Return FSM status actions for ride moderators"""
+    park = get_object_or_404(Park, slug=park_slug)
+    ride = get_object_or_404(Ride, park=park, slug=ride_slug)
+
+    # Only show to moderators
+    if not request.user.has_perm('rides.change_ride'):
+        return HttpResponse("")
+
+    return render(request, "rides/partials/ride_status_actions.html", {
+        "ride": ride,
+        "park": park,
+        "user": request.user
+    })
+
+
+def ride_header_badge(request: HttpRequest, park_slug: str, ride_slug: str) -> HttpResponse:
+    """Return the header status badge partial for a ride"""
+    park = get_object_or_404(Park, slug=park_slug)
+    ride = get_object_or_404(Ride, park=park, slug=ride_slug)
+    return render(request, "rides/partials/ride_header_badge.html", {
+        "ride": ride,
+        "park": park,
+        "user": request.user
+    })
+
+
 class RideDetailView(HistoryMixin, DetailView):
     """View for displaying ride details"""