Bump version and add reusable AppHost package

[Marc-André Moreau (mamoreau-devolutions)]

Summary

• bump multi-pwsh/pwsh-host to 0.13.0 and keep release references aligned
• make scoped install/env/path behavior coherent around user vs machine scope
• add local pwsh/pwsh.exe apphost mode that hosts adjacent pwsh.dll + pwsh.runtimeconfig.json without PATH fallback
• add app-local-first plus nethost/global hostfxr fallback for framework-dependent apphost output
• add inert-by-default Devolutions.MultiPwsh.AppHost NuGet packaging, opt-in MSBuild build/publish copy targets, CI/release wiring, smoke validation, and docs

Validation

• 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 -p:PwshExePath=...
• dotnet test dotnet\bindings\Devolutions.PowerShell.SDK.Bindings.csproj --no-build -p:PwshExePath=...
• tests\Invoke-AppHostNuGetPackageSmokeTest.ps1 against local Devolutions.MultiPwsh.AppHost package
• local renamed-apphost smoke with multi-pwsh.exe copied as pwsh.exe beside a PowerShell 7.4 payload