[REQUEST] adding type hints and `py.typed` metadata

Is your feature request related to a problem? Please describe.

With deepspeed==0.15.4, mypy==1.14.1 reports deepspeed is untyped:

error: Skipping analyzing "deepspeed.utils": module is installed, but missing library stubs or py.typed marker  [import-untyped]
    from deepspeed.utils import logger
    ^
Skipping analyzing "deepspeed.checkpoint.constants": module is installed, but missing library stubs or py.typed marker  [import-untyped]
    from deepspeed.checkpoint.constants import (
    ^

This is because deepspeed doesn't have either type hints or a py.typed marker file.

Describe the solution you'd like

Adding type hints and a py.typed marker file so type checkers can inspect deepspeed to prevent TypeError-related bugs.

Describe alternatives you've considered

A workaround is to disable this error via mypy configuration:

[[tool.mypy.overrides]]
ignore_missing_imports = true
module = [
    "deepspeed.*",
]

Additional context

N/a