refactor: restructure lidarlib into xlidar-driver plugin SDK

- LidarManager facade (liblidar_manager.so): dlopen plugin discovery,
  available_drivers map<driver_id, PluginRegistry>, create_lidar_device,
  config.json load/save with legacy lidarlib migration
- Common LidarDriverInterface + DriverInfo/DeviceConfig plugin ABI
  (extern C get_driver_info / create_driver_instance)
- Plugins: driver_rplidar (ported from xlocd, Slamtec SDK), driver_olei,
  driver_sick_code (TiM CoLa-A), driver_sick_safety (nanoScan3), driver_espe
- Diagnostics extended with rplidar health + firmware; FOV filter window,
  range override and legacy remap window unified in DeviceConfig
- Rewritten README, diagnostics doc and examples (list_drivers, example,
  lidar_app)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

plugins/driver_rplidar/CMakeLists.txt

@@ -0,0 +1,35 @@
+# The rplidar plugin compiles the vendor SDK straight into the plugin .so.
+# XLIDAR_RPLIDAR_SDK_DIR must point at a directory holding include/ + src/;
+# when unset, common local layouts are probed. Without an SDK the plugin is
+# skipped (the rest of the build is unaffected).
+
+if(NOT XLIDAR_RPLIDAR_SDK_DIR)
+    foreach(candidate
+            ${CMAKE_SOURCE_DIR}/third_party/rplidar_sdk
+            ${CMAKE_SOURCE_DIR}/../rplidar_sdk/sdk
+            ${CMAKE_SOURCE_DIR}/../xloc-monorepo/xlocd/deps/rplidar_sdk)
+        if(EXISTS ${candidate}/include/sl_lidar.h)
+            set(XLIDAR_RPLIDAR_SDK_DIR ${candidate})
+            break()
+        endif()
+    endforeach()
+endif()
+
+if(NOT XLIDAR_RPLIDAR_SDK_DIR OR NOT EXISTS ${XLIDAR_RPLIDAR_SDK_DIR}/include/sl_lidar.h)
+    message(WARNING "driver_rplidar: Slamtec SDK not found "
+                    "(set -DXLIDAR_RPLIDAR_SDK_DIR=...) — plugin skipped")
+    return()
+endif()
+
+message(STATUS "driver_rplidar: using SDK at ${XLIDAR_RPLIDAR_SDK_DIR}")
+
+file(GLOB_RECURSE RPLIDAR_SDK_SOURCES CONFIGURE_DEPENDS
+    ${XLIDAR_RPLIDAR_SDK_DIR}/src/*.cpp)
+# The SDK ships win32/macOS arch files; keep Linux only.
+list(FILTER RPLIDAR_SDK_SOURCES EXCLUDE REGEX "arch/(win32|macOS)/")
+
+xlidar_add_plugin(driver_rplidar rplidar_driver.cpp ${RPLIDAR_SDK_SOURCES})
+target_include_directories(driver_rplidar SYSTEM PRIVATE
+    ${XLIDAR_RPLIDAR_SDK_DIR}/include
+    ${XLIDAR_RPLIDAR_SDK_DIR}/src
+)