docs: document ROS2 color queue diagnostics

docs/en/source/camera_devices/4_application_guide/launch_parameters.md

@@ -65,6 +65,8 @@ The following are the launch parameters available:
     *   For lower CPU usage, see the `color_format` recommendations in [Lower CPU Usage](../5_advanced_guide/performance/lower_cpu_usage.md).
 *   **`enable_[color|depth|left_ir|right_ir|ir]`**
     *   Enable or disable the corresponding image stream.
+*   **`color_frame_queue_max_frames`**, **`left_color_frame_queue_max_frames`**, **`right_color_frame_queue_max_frames`**
+    *   Set the maximum number of color frames buffered by the corresponding color-frame worker. The default is `10`; when the queue is full, the oldest frame is discarded and the overflow counter is incremented. The current queue size and overflow counters can be queried with `/camera/get_color_queue_stats`.
 *   **`[color|depth|left_ir|right_ir|ir]_rotation`**
     *   Set stream image rotation.
     *   The possible values are `0`, `90`, `180`, `270`.

docs/en/source/camera_devices/4_application_guide/services.md

@@ -108,6 +108,22 @@
     ros2 service call /camera/set_streams_enable std_srvs/srv/SetBool '{data: false}'
     ```
 
+### Color Queue Diagnostics
+
+* `/camera/get_color_queue_stats`
+
+This service uses `std_srvs/srv/SetBool`. Pass `false` to query the current statistics, or `true` to query and reset the accumulated statistics.
+
+```bash
+ros2 service call /camera/get_color_queue_stats std_srvs/srv/SetBool '{data: false}'
+```
+
+The JSON response in `message` contains the total `overflow_count` and a `queues` object. Each enabled queue reports `capacity_frames`, `queue_size`, `max_queue_size`, `overflow_count`, `oldest_queue_wait_ms`, and `max_queue_wait_ms`. The service also reports the node `namespace` and whether the statistics were reset in `statistics_reset`.
+
+```bash
+ros2 service call /camera/get_color_queue_stats std_srvs/srv/SetBool '{data: true}'
+```
+
 ### Runtime Stream Configuration
 
 *   `/camera/set_stream_profile`