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.

openapi.yaml

@@ -3857,6 +3857,13 @@ paths:
           schema:
             type: integer
             minimum: 1
+        - name: dynamic_image_id
+          in: query
+          required: false
+          description: Dynamic image ID to preview instead of the lane's saved image
+          schema:
+            type: integer
+            minimum: 1
         - name: buttons
           in: query
           required: false
@@ -7803,6 +7810,93 @@ paths:
         '404':
           $ref: '#/components/responses/NotFound'
 
+  /relay/machine/on/post:
+    get:
+      tags:
+        - Plate Scans
+      summary: Record Shelly machine ON signal webhook
+      description: Accepts Shelly Cloud webhook/query parameters for input.toggle_on or switch.on and records the physical machine start signal for self-serve billing.
+      operationId: recordShellyMachineOnSignal
+      parameters:
+        - name: token
+          in: query
+          required: false
+          schema: {type: string}
+        - name: lane_id
+          in: query
+          required: false
+          schema:
+            type: integer
+        - name: relay_id
+          in: query
+          required: false
+          schema:
+            type: string
+        - name: event
+          in: query
+          required: false
+          schema:
+            type: string
+            enum: [input.toggle_on, switch.on]
+        - name: reg
+          in: query
+          required: false
+          schema:
+            type: string
+      responses:
+        '201':
+          description: Machine ON signal recorded and linked to a self-serve wash session
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/MachineButtonPressWebhookResponse'
+        '202':
+          description: Shelly signal was recognized but ignored
+        '400':
+          $ref: '#/components/responses/BadRequest'
+    post:
+      tags:
+        - Plate Scans
+      summary: Record Shelly machine ON signal webhook
+      description: Accepts Shelly Cloud JSON webhook payloads for input.toggle_on or switch.on and records the physical machine start signal for self-serve billing.
+      operationId: recordShellyMachineOnSignalPost
+      requestBody:
+        required: false
+        content:
+          application/json:
+            schema:
+              type: object
+              properties:
+                token:
+                  type: string
+                lane_id:
+                  type: integer
+                relay_id:
+                  type: string
+                event:
+                  type: string
+                  enum: [input.toggle_on, switch.on]
+                component:
+                  type: string
+                  example: input:0
+                state:
+                  type: boolean
+                output:
+                  type: boolean
+                reg:
+                  type: string
+      responses:
+        '201':
+          description: Machine ON signal recorded and linked to a self-serve wash session
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/MachineButtonPressWebhookResponse'
+        '202':
+          description: Shelly signal was recognized but ignored
+        '400':
+          $ref: '#/components/responses/BadRequest'
+
   # Module - e-conomic Endpoints
   /economic/customers/import:
     post: