feat: initial ROS2 vision pipeline with gimbal control and nginx config

- camera_node (driver_pkg): Hikrobot MvCamera SDK image capture
- vision_node (algorithm_pkg): Otsu threshold + contour detection + target tracking
- web_node (application_pkg): HTTP server with MJPEG preview and mode switch API
- gimbal_node (gimbal_control_pkg): UART serial communication per gimbal protocol
- bringup_pkg: launch file for full pipeline
- config: nginx reverse-proxy for MJPEG streaming and API routing

workspace/src/bringup_pkg/launch/vision_pipeline.launch.py

@@ -0,0 +1,35 @@
+from launch import LaunchDescription
+from launch_ros.actions import Node
+
+
+def generate_launch_description():
+    return LaunchDescription([
+        Node(
+            package='driver_pkg',
+            executable='camera_node',
+            name='camera_node',
+            output='screen',
+        ),
+        Node(
+            package='algorithm_pkg',
+            executable='vision_node',
+            name='vision_node',
+            output='screen',
+        ),
+        Node(
+            package='application_pkg',
+            executable='web_node',
+            name='web_node',
+            output='screen',
+        ),
+        Node(
+            package='gimbal_control_pkg',
+            executable='gimbal_node',
+            name='gimbal_node',
+            output='screen',
+            parameters=[{
+                'serial_port': '/dev/ttyTHS0',
+                'baud_rate': 115200,
+            }],
+        ),
+    ])