feat: add HTTP API for image retrieval from camera; implement endpoint for accessing latest image frames

worker.md

@@ -439,3 +439,45 @@ This section shows a typical sequence of messages between the backend and the wo
       "cameraConnections": []
     }
     ```
+## 7. HTTP API: Image Retrieval
+
+In addition to the WebSocket protocol, the worker exposes an HTTP endpoint for retrieving the latest image frame from a camera.
+
+### Endpoint
+
+```
+GET /camera/{camera_id}/image
+```
+
+- **`camera_id`**: The full `subscriptionIdentifier` (e.g., `display-001;cam-001`).
+
+### Response
+
+- **Success (200):** Returns the latest JPEG image from the camera stream.
+    - `Content-Type: image/jpeg`
+    - Binary JPEG data.
+
+- **Error (404):** If the camera is not found or no frame is available.
+    - JSON error response.
+
+- **Error (500):** Internal server error.
+
+### Example Request
+
+```
+GET /camera/display-001;cam-001/image
+```
+
+### Example Response
+
+- **Headers:**
+    ```
+    Content-Type: image/jpeg
+    ```
+- **Body:** Binary JPEG image.
+
+### Notes
+
+- The endpoint returns the most recent frame available for the specified camera subscription.
+- If multiple displays share the same camera, each subscription has its own buffer; the endpoint uses the buffer for the given `camera_id`.
+- This API is useful for debugging, monitoring, or integrating with external systems that require direct image access.