feat: add EskinDeviceFunc FFI bindings and update Python/README

- Add FFI wrappers for all EskinDeviceFunc trait methods:
  eskin_read_hdw_version, eskin_read_matrix_row/col,
  eskin_read_device_config1/2, eskin_write_device_config1/2,
  eskin_write_matrix_row/col
- Extract sdk_error_to_code() helper for SdkError -> SdkErrorCode conversion
- Update C header (include/eskin_ffi.h) with new function declarations
- Update Python FFI bindings (example/python/eskin_ffi.py) with new methods
- Update README with Python usage instructions and full FFI interface table

README.md

@@ -98,18 +98,30 @@ int main() {
 
 ## 使用 Python
 
+### 构建 & 准备
+
 ```bash
 cargo build --release
+# 将生成的 .so 文件复制到 python 示例目录下
+cp target/release/libeskin_finger_sdk.so example/python/
 cd example/python
-LD_LIBRARY_PATH=../../target/release python3 example.py
+python3 example.py
 ```
 
+> **注意：** Python 示例默认从当前目录加载 `libeskin_finger_sdk.so`，请确保 `.so` 文件已复制到 `example/python/` 目录下，或修改 `example.py` 中的 `LIB_PATH` 指向正确的路径。
+
 ```python
 from eskin_ffi import EskinDevice
 
-with EskinDevice("target/release/libeskin_finger_sdk.so") as dev:
+with EskinDevice("libeskin_finger_sdk.so") as dev:
     dev.open("/dev/ttyUSB0")
 
+    # 读取硬件版本
+    print(f"Hardware version: {dev.read_hdw_version()}")
+
+    # 读取矩阵尺寸
+    print(f"Matrix: {dev.read_matrix_row()} x {dev.read_matrix_col()}")
+
     # 读寄存器
     data = dev.read_register(0x0000, 4)
     print(f"Serial: {data.hex()}")
@@ -129,6 +141,15 @@ with EskinDevice("target/release/libeskin_finger_sdk.so") as dev:
 | `eskin_close(handle)` | 关闭设备，释放 handle |
 | `eskin_read_register(handle, addr, length, buf, buf_len, actual_len)` | 读寄存器原始字节 |
 | `eskin_write_register(handle, addr, data, data_len, return_count)` | 写寄存器原始字节 |
+| `eskin_read_hdw_version(handle, buf, buf_len, actual_len)` | 读取硬件版本号 |
+| `eskin_read_matrix_row(handle, out)` | 读取矩阵行数 |
+| `eskin_read_matrix_col(handle, out)` | 读取矩阵列数 |
+| `eskin_read_device_config1(handle, out)` | 读取设备配置寄存器1 |
+| `eskin_read_device_config2(handle, out)` | 读取设备配置寄存器2 |
+| `eskin_write_device_config1(handle, enable, return_count)` | 写入设备配置寄存器1 |
+| `eskin_write_device_config2(handle, enable, return_count)` | 写入设备配置寄存器2 |
+| `eskin_write_matrix_row(handle, row, return_count)` | 写入矩阵行数 |
+| `eskin_write_matrix_col(handle, col, return_count)` | 写入矩阵列数 |
 
 ---