refactor(storage): add checksum validation robustness and leak prevention

[chandra-siri]

Validate type/range of full_object_checksum and wrap stream finalization in try...finally to prevent stream leaks on error.

[gemini-code-assist]

Code Review

This pull request introduces an enable_checksum option to the asynchronous appendable object writer and writes resumption strategy, allowing users to disable CRC32C checksum calculation. It also adds validation for full_object_checksum in finalize and wraps the finalization response handling in a try...finally block to guarantee stream closure and state reset on failure. Unit tests have been added to cover these changes. Feedback is provided regarding the type check for full_object_checksum in finalize, noting that isinstance(..., int) will evaluate to True for boolean values because bool is a subclass of int in Python, and suggesting an explicit check to reject booleans.

[gemini-code-assist]

In Python, bool is a subclass of int, so isinstance(True, int) evaluates to True. If a boolean value is passed as full_object_checksum, it will bypass this type check and be treated as a valid checksum (e.g., 1 or 0).

To prevent this, explicitly reject boolean values.

Suggested change

	if not isinstance(full_object_checksum, int):
	raise TypeError("full_object_checksum must be an integer.")
	if not isinstance(full_object_checksum, int) or isinstance(full_object_checksum, bool):
	raise TypeError("full_object_checksum must be an integer.")