fix(headless): Set DX8Wrapper_IsWindowed to false to suppress assertion dialogs during shutdown

[bobtista]

Summary

• Set DX8Wrapper_IsWindowed to false in headless mode so ignoringAsserts() works - particularly during shutdown after TheGlobalData has been destroyed.

Testing

• Run headless replay to completion (-replay test.rep -headless -ignoreAsserts)
• Verify no assertion dialogs appear during shutdown

[greptile-apps]

Greptile Summary

Refactored headless mode initialization by moving the DX8Wrapper_IsWindowed fix from WinMain.cpp into the parseHeadless() function in CommandLine.cpp. This consolidates headless-related initialization logic in one place and makes the code cleaner. The fix addresses a critical issue where assertion dialogs could appear during shutdown in headless mode after TheGlobalData is destroyed, by ensuring ignoringAsserts() returns early without accessing the destroyed object.

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• This is a clean refactoring that moves existing, tested code to a more appropriate location. The original fix was already tested and merged (commit 6826644), and this PR simply relocates it to consolidate headless initialization logic. No behavioral changes are introduced.
• No files require special attention

Important Files Changed

Filename	Overview
GeneralsMD/Code/GameEngine/Source/Common/CommandLine.cpp	Moved DX8Wrapper_IsWindowed initialization from WinMain into parseHeadless() for better code organization

_{Last reviewed commit: 3e96876}