Git for Windows can completely fail to write files during clone due to
antivirus software, Windows Defender Controlled Folder Access, or NTFS
filter drivers. Even with windows.appendAtomically=false, the checkout
phase fails with 'unable to create file: Invalid argument'.
New install strategy (3 attempts):
1. git clone with -c windows.appendAtomically=false (SSH then HTTPS)
2. If clone fails: download GitHub ZIP archive, extract with
Expand-Archive (Windows native, no git file I/O), then git init
the result for future updates
3. All git commands now use -c flag to inject the atomic write fix
Also passes -c flag on update path (fetch/checkout/pull) and makes
submodule init failure non-fatal with a warning.
4766b3cdb9