Add checksum verification for release installs

[Marc-André Moreau (mamoreau-devolutions)]

Summary

• validate GitHub release archives against SHA-256 checksums before extraction and install
• decode and parse real PowerShell hashes.sha256 assets, including UTF-16LE BOM content and common checksum line formats
• add CLI controls to skip checksum verification or provide an explicit checksum file by URL or local path

Verification

• cargo fmt --all --check
• cargo clippy --workspace --all-targets
• cargo build --all-targets
• cargo test --all-targets
• dotnet build dotnet/bindings/Devolutions.PowerShell.SDK.Bindings.csproj
• dotnet test dotnet/bindings/Devolutions.PowerShell.SDK.Bindings.csproj --no-build
• smoke-tests workflow run 24158181093