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/parks/views.py

@@ -132,6 +132,29 @@ def park_actions(request: HttpRequest, slug: str) -> HttpResponse:
     return render(request, "parks/partials/park_actions.html", {"park": park})
 
 
+def park_status_actions(request: HttpRequest, slug: str) -> HttpResponse:
+    """Return FSM status actions for park moderators"""
+    park = get_object_or_404(Park, slug=slug)
+
+    # Only show to moderators
+    if not request.user.has_perm('parks.change_park'):
+        return HttpResponse("")
+
+    return render(request, "parks/partials/park_status_actions.html", {
+        "park": park,
+        "user": request.user
+    })
+
+
+def park_header_badge(request: HttpRequest, slug: str) -> HttpResponse:
+    """Return the header status badge partial for a park"""
+    park = get_object_or_404(Park, slug=slug)
+    return render(request, "parks/partials/park_header_badge.html", {
+        "park": park,
+        "user": request.user
+    })
+
+
 def get_park_areas(request: HttpRequest) -> HttpResponse:
     """Return park areas as options for a select element"""
     park_id = request.GET.get("park")