fix(setup): inspect signer through native provider

[Sykezzz]

Summary

• run the bounded silent signer inspection through native Windows PowerShell when Setup is launched from its 32-bit host
• preserve the existing exact SHA, private-key, EKU, trust-store, and timeout checks
• add a regression contract for the native provider path

Verification

• uv run pytest tests/test_build_profiles.py -q (11 passed)
• pinned native Windows build of both profiles and unified Inno Setup 7.0.2 EXE completed successfully
• no local certificate enrollment or application installation was performed