fix: recurse into tuples in deepcopy_minimal to prevent mutation

deepcopy_minimal only copied dicts and lists, leaving tuples
as-is. When a FileTypes tuple like (name, content, mime, headers)
was passed to files.beta.upload, the headers Mapping inside the
tuple could be mutated in-place, corrupting the caller's data.

Fixes #1202

Author: Scottcjn

src/anthropic/_utils/_utils.py

@@ -181,13 +181,16 @@ def deepcopy_minimal(item: _T) -> _T:
 
     - mappings, e.g. `dict`
     - list
+    - tuple (recursed but preserved as tuple)
 
     This is done for performance reasons.
     """
     if is_mapping(item):
         return cast(_T, {k: deepcopy_minimal(v) for k, v in item.items()})
     if is_list(item):
         return cast(_T, [deepcopy_minimal(entry) for entry in item])
+    if isinstance(item, tuple):
+        return cast(_T, tuple(deepcopy_minimal(entry) for entry in item))
     return item