CommaSplitter treats backslash as an escape character, which breaks
Windows paths like C:\Users\foo since \U is not a valid escape. On
Windows, treat backslash as a literal character outside of quoted
strings. Inside quotes, escape sequences still work as before.
The platform behavior is controlled by a single comptime constant
(escape_outside_quotes) so the logic lives in one place. Escape-specific
tests are skipped on Windows with SkipZigTest, and Windows-specific
tests are added separately.
Also fix Theme.parseCLI to not mistake the colon in a Windows drive
letter (C:\...) for a light/dark theme pair separator.
Note: other places in the config parsing also use colon as a delimiter
without accounting for Windows drive letters (command.zig prefix
parsing, keybind parsing). Those are tracked separately.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
