Add unit tests for department lane dynamic image overrides and introduce classes for self-serve signal and virtual hardware management

- Add `DepartmentLaneDynamicImageRouteTest` to verify dynamic image preview handling for studio lanes.
- Introduce `selfserve_machine_signal` class to standardize signal normalization, recording, and gateway signal management workflows.
- Add `selfserve_virtual_hardware` class to handle virtual hardware configurations, including gateway and binding management.
- Enhance structure with auxiliary methods for payload normalization, workspace merging, and validation warnings.

services/nginx/app/tests/Unit/DynamicImages/DynamicImagePreRenderCronWiringTest.php

@@ -9,6 +9,8 @@ it('registers dynamic image pre-render cron task and related helpers', function
     expect($content)->toContain('collectDynamicImageTaskGroupsForLane');
     expect($content)->toContain('buildDynamicImageVariantsForTaskGroup');
     expect($content)->toContain('renderDynamicImageVariant');
+    expect($content)->toContain('mergeUniqueButtonValues');
+    expect($content)->toContain('normalizeButtonsInput');
     expect($content)->toContain('dynamic_image:');
     expect($content)->toContain('machine_1');
 });