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>

examples/list_drivers.cpp

@@ -0,0 +1,28 @@
+// Discover plugins and print every registered driver.
+//   ./list_drivers [plugins_dir]        (default: ./plugins)
+#include "lidar_manager.hpp"
+#include <cstdio>
+
+int main(int argc, char** argv) {
+    const std::string plugins_dir = (argc > 1) ? argv[1] : "plugins";
+
+    xlidar::LidarManager manager(plugins_dir);
+    size_t count = manager.load_all_plugins();
+    printf("%zu driver(s) in %s\n\n", count, plugins_dir.c_str());
+
+    for (const auto& [driver_id, plugin] : manager.available_drivers()) {
+        const xlidar::DriverInfo& info = plugin.info;
+        printf("%s\n", driver_id.c_str());
+        printf("  vendor:      %s\n", info.vendor.c_str());
+        printf("  model:       %s\n", info.model.c_str());
+        printf("  transport:   %s%s\n", xlidar::to_string(info.transport),
+               info.transport_selectable ? " (selectable)" : "");
+        printf("  models:      ");
+        for (size_t i = 0; i < info.supported_models.size(); ++i)
+            printf("%s%s", i ? ", " : "", info.supported_models[i].c_str());
+        printf("\n");
+        printf("  description: %s\n", info.description.c_str());
+        printf("  file:        %s\n\n", plugin.file_path.c_str());
+    }
+    return 0;
+}