Windows contributor setup references an untracked setup.bat

The automated setup section in docs/CONTRIBUTING.md tells Windows contributors to run setup.bat from a VS 2022 Developer Command Prompt, but that file is absent from the repository.

Checked at 73e192986aa6133d69ec306ebbd4eb9befbe43ac:

• Documented command.
• git ls-files --error-unmatch setup.bat fails because the path is not tracked; setup.sh and fincept-qt/CMakePresets.json are tracked.
• GETTING_STARTED.md already gives the Windows CMake commands.

A new Windows contributor following the recommended automated setup cannot run its first command. I propose removing the unavailable Windows launcher from that code block and pointing Windows contributors to the existing manual setup section. This would avoid introducing another setup script to maintain.

Per the contribution policy, I'm requesting scope approval before preparing a docs PR. Would you prefer that correction, or is a Windows launcher intended to be restored?