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/classes/selfserve_schema_bootstrap.php

@@ -126,6 +126,19 @@ class selfserve_schema_bootstrap
                 INDEX idx_department_selfserve_studio_layouts_department_user (department_id, user_id),
                 INDEX idx_department_selfserve_studio_layouts_department_updated (department_id, updated_at)
             ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci",
+
+            "CREATE TABLE IF NOT EXISTS department_selfserve_studio_virtual_hardware (
+                id INT AUTO_INCREMENT PRIMARY KEY,
+                department_id INT NOT NULL,
+                config_json JSON NOT NULL,
+                created_by INT NULL,
+                updated_by INT NULL,
+                created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+                updated_at TIMESTAMP NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP,
+                deleted_at TIMESTAMP NULL DEFAULT NULL,
+                UNIQUE KEY uniq_selfserve_vhw_department (department_id),
+                INDEX idx_selfserve_vhw_dept_updated (department_id, updated_at)
+            ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci",
         ];
 
         foreach ($queries as $sql) {