Stop repeated installer toolchain startup failures

[JamieW105]

With all optional languages selected, Setup can launch PowerShell up to 15 times for repeated checks and per-language installs. Run all selections in one hidden, noninteractive process as the original user. Stop the batch if WinGet returns 142 or 0xc0000142, skip installed tools, and keep ordinary package failures aggregated.

Record host launch errors and exit codes in an automatic Setup log, resolve the toolchain transcript in the original user's profile, and write a clear package-and-code line for each failed install. Show one optional-toolchain failure while leaving Rustic installed. Validate Inno syntax and Windows PowerShell regression cases before the expensive engine build.

Validation: fresh Windows installer build passed, producing RusticGameEngine-Setup-0.1.0-x64-20261013-212947.exe. All 12 Windows PowerShell regression scenarios and four silent packaged Setup scenarios passed, including all selected languages sharing one host, stopping on initialization failure, keeping the engine installed, and bundled-only Setup skipping the manager. The engine CI jobs on Windows and Linux, language adapter conformance, workflow syntax, secret scan, and Rust dependency audit passed. Local manager smoke checks and all nine installer-release tests also passed.

Tested installer artifact: https://github.com/Rustic-Game-Engine/engine/actions/runs/38469014259/artifacts/11850569802

Build and test logs: https://github.com/Rustic-Game-Engine/engine/actions/runs/38469014259

The original reported error was not reproducible; this change removes repeated host launches and improves diagnosis without claiming a confirmed root cause.

Companion documentation PR: Rustic-Game-Engine/docs#38 (lint, production build, TypeScript, dependency audit, and exported links passed).