On Windows systems where git can't write files (antivirus, NTFS filter
drivers), 'hermes update' now falls back to downloading a ZIP archive
from GitHub and extracting it over the existing installation.
The fallback triggers in two cases:
1. No .git directory (ZIP-installed via install.ps1 fallback)
2. Git pull fails with CalledProcessError on Windows
The ZIP update preserves venv/, node_modules/, .git/, and .env,
reinstalls Python deps via uv, and syncs bundled skills.
Also adds -c windows.appendAtomically=false to all git commands in
the update path for systems where git works but atomic writes fail.
535b46f813