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/build_real.sh

@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+# Build Flexiv hardware packages for real robot (after RDK installed to ~/flexiv_install)
+set -eo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$ROOT"
+
+if [[ -f "${HOME}/anaconda3/etc/profile.d/conda.sh" ]]; then
+  # shellcheck disable=SC1091
+  source "${HOME}/anaconda3/etc/profile.d/conda.sh"
+  set +u
+  conda activate ros_flexiv 2>/dev/null || true
+  set -u 2>/dev/null || true
+fi
+
+if [[ -z "${ROS_DISTRO:-}" ]]; then
+  # shellcheck disable=SC1091
+  source /opt/ros/humble/setup.bash 2>/dev/null || source /opt/ros/jazzy/setup.bash 2>/dev/null || true
+fi
+
+PREFIX="${HOME}/flexiv_install"
+CMAKE_PREFIX="${PREFIX}"
+if [[ -n "${CONDA_PREFIX:-}" ]]; then
+  CMAKE_PREFIX="${PREFIX};${CONDA_PREFIX}"
+fi
+
+colcon build --symlink-install --packages-select \
+  flexiv_hardware \
+  flexiv_msgs \
+  flexiv_gripper \
+  flexiv_test_nodes \
+  flexiv_robot_states_broadcaster \
+  flexiv_bringup \
+  --cmake-args "-DCMAKE_PREFIX_PATH=${CMAKE_PREFIX}" "$@"
+
+echo "Real stack build done. source ${ROOT}/scripts/env.sh"