feat: init sim_smart_car_bridge — ROS2 bridge relay for Origincar HTTP API

Bridge image (GET /image → sensor_msgs/Image), IMU (GET /imu → sensor_msgs/Imu),
and cmd_vel (Twist → POST /cmd) between Origincar simulation and ROS2.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,21 @@
+# Python
+__pycache__/
+*.py[cod]
+*.egg-info/
+
+# Build
+build/
+dist/
+*.egg
+
+# IDE
+.vscode/
+.idea/
+
+# ROS2
+log/
+install/
+
+# OS
+.DS_Store
+Thumbs.db