fix: 解决打包后三个运行时问题

- rthook_paddle.py: stub paddle.utils.cpp_extension，避免Cython缺文件崩溃
- build_exe.py: 显式收集paddle DLLs（mklml.dll等）
- ocr_offline.py: 非ASCII路径自动复制模型到临时目录，绕过PaddlePaddle C++路径限制

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

rthook_paddle.py

@@ -0,0 +1,33 @@
+"""
+PyInstaller runtime hook: stub 掉 paddle 中仅开发时需要的模块，
+避免打包后因缺少 Cython Utility 文件而崩溃。
+"""
+import types
+import sys
+
+
+class _Stub(types.ModuleType):
+    """空模块 stub，所有属性访问返回空类"""
+    def __getattr__(self, name):
+        if name.startswith("_"):
+            raise AttributeError(name)
+        return type(name, (), {})
+
+
+def _inject(name):
+    if name not in sys.modules:
+        m = _Stub(name)
+        m.__path__ = []
+        m.__package__ = name
+        m.__spec__ = None
+        sys.modules[name] = m
+
+
+# paddle.utils.cpp_extension 会拉入 Cython 编译器，推理不需要
+for _p in [
+    "paddle.utils.cpp_extension",
+    "paddle.utils.cpp_extension.cpp_extension",
+    "paddle.utils.cpp_extension.extension_utils",
+    "paddle.utils.cpp_extension.jit_compile",
+]:
+    _inject(_p)