feat: add offline SVG export for rack elevations

Adds a "SVG offline" download button on the rack detail page. It
reuses NetBox's own rack-elevation REST endpoint to render the SVG,
then strips embedded <a>/xlink:href links (which point at internal,
relative NetBox URLs and are useless once the file is saved) so the
result renders identically when opened standalone in any SVG viewer.

Gated by the new offline_svg_export_enabled plugin setting (on by
default).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

netbox_utilities/views.py

@@ -1,10 +1,10 @@
-from dcim.models import Device, Module
+from dcim.models import Device, Module, Rack
 from django.contrib import messages
 from django.contrib.auth.mixins import LoginRequiredMixin, UserPassesTestMixin
 from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import SuspiciousFileOperation, ValidationError
 from django.db import DatabaseError, transaction
-from django.http import Http404, HttpResponseBadRequest, JsonResponse
+from django.http import Http404, HttpResponse, HttpResponseBadRequest, JsonResponse
 from django.shortcuts import get_object_or_404, redirect, render
 from django.urls import reverse
 from django.utils.http import url_has_allowed_host_and_scheme
@@ -33,8 +33,10 @@ from .navigation_helpers import (
 from .runtime import (
     clear_runtime_settings_cache,
     navigation_customization_enabled,
+    offline_svg_export_enabled,
     tenant_filter_enabled,
 )
+from .svg_export import strip_svg_hyperlinks
 
 
 def _safe_return_url(request, default_name="home"):
@@ -364,3 +366,35 @@ class SelectTenantView(LoginRequiredMixin, View):
             return HttpResponseBadRequest("Ungültiger Mandantenfilter.")
 
         return redirect(_safe_return_url(request))
+
+
+class RackElevationOfflineSVGView(LoginRequiredMixin, View):
+    """Serve a rack elevation SVG stripped of hyperlinks, for offline use."""
+
+    def get(self, request, pk):
+        if not offline_svg_export_enabled():
+            return HttpResponseBadRequest("Der Offline-SVG-Export ist deaktiviert.")
+
+        rack = get_object_or_404(Rack.objects.restrict(request.user, "view"), pk=pk)
+        face = request.GET.get("face", "front")
+        if face not in ("front", "rear"):
+            return HttpResponseBadRequest("Ungültige Rack-Seite.")
+
+        from dcim.api.views import RackViewSet
+        from rest_framework.test import APIRequestFactory
+
+        factory = APIRequestFactory()
+        api_request = factory.get(
+            f"/api/dcim/racks/{rack.pk}/elevation/",
+            {"render": "svg", "face": face},
+        )
+        api_request.user = request.user
+        drf_view = RackViewSet.as_view({"get": "elevation"})
+        response = drf_view(api_request, pk=rack.pk)
+        response.render()
+
+        offline_svg = strip_svg_hyperlinks(response.content)
+        filename = f"{rack.name}-{face}-offline.svg".replace(" ", "_")
+        http_response = HttpResponse(offline_svg, content_type="image/svg+xml")
+        http_response["Content-Disposition"] = f'attachment; filename="{filename}"'
+        return http_response