fix: restrict proxy content access and scope backup storage to owners

- Hide proxy configuration contents from users without update permission.
- Select and validate backup S3 storage against the resource's team.
- Keep scheduled branch syncs green while a conflict PR remains open.
- Document external mount permissions and Sentinel traffic limits.
- Add regression coverage for authorization and backup storage selection.

resources/views/livewire/server/proxy/dynamic-configurations.blade.php

@@ -63,8 +63,14 @@
                                             wire:key="proxy-navbar-{{ $fileName }}" />
                                     @endif
                                 </x-slot:actions>
-                                <x-forms.textarea disabled wire:model="contents.{{ $fileName }}"
-                                    rows="8" />
+                                @can('update', $server)
+                                    <x-forms.textarea disabled wire:model="contents.{{ $fileName }}"
+                                        rows="8" />
+                                @else
+                                    <p class="text-xs text-neutral-500 dark:text-fg-dim">
+                                        You do not have permission to view the contents of this configuration.
+                                    </p>
+                                @endcan
                             </x-application.settings-section>
                         @endforeach
                     @else