Add patch activation callback

[Sushisource]

What was changed

Added an experimental Worker(..., patch_activation_callback=...) option that lets a worker decide whether the first newly encountered, non-replay workflow.patched call activates a patch.

The callback receives frozen PatchActivationInput containing workflow information and the patch ID. Its strict boolean decision is memoized for the workflow run. Declined patches return False without recording a marker, while replay, existing history markers, and deprecated patches retain their existing behavior. Replayers do not invoke the callback.

This ports the behavior introduced by temporalio/sdk-ruby#481.

Why?

This allows workflow changes using workflow.patched to roll out gradually without every new-code worker immediately recording a marker that older workers cannot replay.

Testing

• Focused patch activation and rolling-worker scenarios: 11
• Targeted mypy checks
• Ruff import and formatting checks
• Diff and sdk-core submodule cleanliness checks