Intentional deviation from Ghostty 1.3.1 (DEVIANT_FIXES.md row 38).
Zig's Theme.parseCLI (config/Config.zig:9788-9799) treats any value
containing ',', '=' or ':' as a light/dark pair. Every absolute Windows
path (C:\themes\x, \\?\C:\..., \\server\share\x) contains a colon, so
Ghostty on Windows rejects all absolute theme paths.
A value that is a single Windows absolute path is now taken as a theme
path; the light:/dark: pair syntax still works, including with drive
paths as values.
Test Plan:
- cargo test -p ghostty-config windows_absolute_path_detection
theme_windows_absolute_path_and_pair_with_paths