Align Windows overlapped signatures - #9566

Summary

• Match 14 Windows _overlapped function and method parameter names to CPython 3.15 Clinic signatures.
• Expose native False/0 defaults for Overlapped.getresult, WSARecv, and WSARecvFrom. The omitted values remain Rust bool/u32; there is no Python default-object allocation or conversion.
• Leave WSARecvFromInto and the existing Rust test untouched in this change.

The 17 targeted entries were present in the Windows whats_left report. Signatures and calling conventions were checked against CPython v3.15.0 Clinic output.

Validation

• Independent source review checked all target names, positional-only binding, arity and conversion order, direct scalar defaults, and unchanged Windows operations. This is source review, not an execution claim.
• rustfmt --edition 2024 --check and git diff --check passed; the normal commit hook passed all applicable checks, including rustfmt and cspell.
• Local compilation, workspace/C API tests and RustPython runtime checks were not run: the coordinated native execution guard and lock are absent, and the offline dependency cache is incomplete. Windows CI is required for target compilation and execution; no hosted pass is claimed.

AI assistance

Implementation and source review were assisted by dot. The runtime does not expose its exact model version.