fix(ctypes): validate argument types before binding shared library functions

- Add explicit validation for ctypes function argument declarations before
assigning them to the loaded shared library function.

- This provides clearer error messages when invalid Python types are passed
to `argtypes`, instead of exposing the internal ctypes error about missing
`from_param()` methods.

Signed-off-by: JamePeng <jame_peng@sina.com>

Author: JamePeng

llama_cpp/_ctypes_extensions.py

@@ -244,6 +244,18 @@ def decorator(f: F) -> F:
                     func = getattr(lib, symbol_name)
                 except AttributeError:
                     continue
+                # Validate ctypes argument declarations before assigning them.
+                # ctypes requires every argtype to provide from_param().
+                for index, argtype in enumerate(argtypes):
+                    if not hasattr(argtype, "from_param"):
+                        raise TypeError(
+                            "Invalid ctypes argument type:\n"
+                            f"  function: {f.__name__}\n"
+                            f"  symbol: {symbol_name}\n"
+                            f"  arg index: {index}\n"
+                            f"  arg type: {argtype!r}\n"
+                            f"  expected: a ctypes type with from_param()"
+                        )
 
                 func.argtypes = argtypes
                 func.restype = restype