chore: 框架科学优化前的完整基线

在开始'设备契约层 + 目录重构 + 通止规装配'改造之前，先钉住当前可运行状态，
使后续任何删除/重构都可回退。

本基线包含：
- 现有 ROS 2 工作区全部源码（arm_application / arm_control / arm_bringup 等）
- 官方 flexiv_ros2 栈（含 flexiv_hardware / flexiv_controllers 等符号链接）
- 设备契约层 src/arm_interfaces（新增，46 项单测通过）
- devices/ 设备选型与品牌清单（新增）
- scripts/gen_site_example.py 与由它生成的 config/site.example.yaml

按 .gitignore 排除：build/ / install/ / log/ / config/site.yaml / 模型权重二进制。

scripts/run_camera_d435.sh

@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+# Overhead D435 between the two arms (eye-to-hand). Does not open either D405.
+#
+#   bash ~/ros2/scripts/run_camera_d435.sh --preview
+#
+set -eo pipefail
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+PREVIEW=1
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    --preview) PREVIEW=1; shift ;;
+    --no-preview) PREVIEW=0; shift ;;
+    -h|--help) sed -n '2,8p' "$0"; exit 0 ;;
+    *) echo "Unknown: $1" >&2; exit 1 ;;
+  esac
+done
+# shellcheck disable=SC1091
+source "${ROOT}/scripts/env.sh"
+# shellcheck disable=SC1091
+source "${ROOT}/scripts/lib/load_site_config.sh"
+SN="${SITE_D435_SERIAL:-}"
+if [[ -z "${SN}" ]]; then
+  echo "ERROR: cameras.d435.serial empty in site.yaml" >&2
+  exit 2
+fi
+echo "=== D435 overhead serial=${SN}  ${SITE_D435_WIDTH:-1280}x${SITE_D435_HEIGHT:-720}@${SITE_D435_FPS:-30} ==="
+pkill -f 'camera_name:=d435' 2>/dev/null || true
+CAM_ARGS=(
+  --ros-args
+  -p camera_name:=d435
+  -p camera_serial:="${SN}"
+  -p width:="${SITE_D435_WIDTH:-1280}"
+  -p height:="${SITE_D435_HEIGHT:-720}"
+  -p fps:="${SITE_D435_FPS:-30}"
+  -p enable_depth:=true
+  -p enable_infra:=false
+  -p preview_stereo:=false
+  -p auto_exposure:=true
+  -p ae_limit_us:=8000
+  -p emitter_enabled:=true
+)
+if [[ "${PREVIEW}" == "1" ]]; then
+  pkill -f 'lib/arm_application/realsense_view' 2>/dev/null || true
+  ros2 run arm_application realsense_color_pub "${CAM_ARGS[@]}" -p show_preview:=false &
+  CAM_PID=$!
+  trap 'kill "${CAM_PID}" 2>/dev/null || true' EXIT INT TERM
+  ros2 run arm_application realsense_view --ros-args -p camera_name:=d435
+else
+  exec ros2 run arm_application realsense_color_pub "${CAM_ARGS[@]}"
+fi