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_sick_safety/sick_safety_driver.hpp

@@ -0,0 +1,63 @@
+// SICK nanoScan3 / microScan3 safety scanners over UDP — plugin-private header.
+#pragma once
+#include "lidar_interface.hpp"
+
+#include <cstdint>
+#include <string>
+#include <vector>
+
+namespace xlidar {
+
+inline constexpr ModelConfig MODEL_SICK_NANOSCAN3 { "SICK-nanoScan3", -137.5f, 137.5f, 0.05f, 40.f };
+
+// SICK nanoScan3 / microScan3 safety-scanner binary UDP output. Layout ported
+// from SICK's open-source sick_safetyscanners; NOT verified on real hardware.
+// Passive UDP receiver: the sensor's UDP target must be configured up front in
+// SICK Safety Designer — this class does no CoLa2/TCP handshake.
+class SickSafetyDriver : public LidarDriverInterface {
+public:
+    // ip: local bind address; port: local UDP port the sensor sends to;
+    // inverted: unit mounted upside-down → mirror the scan.
+    explicit SickSafetyDriver(const ModelConfig& cfg,
+                              const std::string& ip       = "0.0.0.0",
+                              uint16_t            port     = 6060,
+                              bool                inverted = false);
+    ~SickSafetyDriver();
+
+    SickSafetyDriver(const SickSafetyDriver&)            = delete;
+    SickSafetyDriver& operator=(const SickSafetyDriver&) = delete;
+
+    DriverInfo get_driver_info() const override;
+
+    ErrorCode open() override;
+    void close() override;
+    bool recv_scan(ScanResult& out, int timeout_ms = 1000) override;
+    void set_scan_callback(ScanCallback cb) override { cb_ = std::move(cb); }
+    bool spin_once() override;
+    bool is_open() const override { return sock_fd_ >= 0; }
+
+    // No model string on the wire — returns the configured name.
+    const char* detected_model() const override { return detected_model_name_.c_str(); }
+
+    Diagnostics get_diagnostics() const override { return latest_diag_; }
+
+private:
+    int  recv_datagram(int timeout_ms);
+    bool parse_packet(const uint8_t* buf, int len, ScanResult& out);
+
+    ModelConfig  cfg_;
+    std::string  detected_model_name_;  // owned copy of cfg_.name (stable lifetime)
+    std::string  ip_;
+    uint16_t     port_;
+    bool         inverted_ = false;
+    int          sock_fd_ = -1;
+    ScanCallback cb_;
+
+    // Snapshot for get_diagnostics(); refreshed by parse_packet().
+    Diagnostics latest_diag_;
+
+    // Per-instance; sized for a full safety-data packet (max ~2751 beams).
+    std::vector<uint8_t> recv_buf_;
+};
+
+} // namespace xlidar