This PR addresses
https://github.com/ghostty-org/ghostty/discussions/12108 implemented
similarly to https://github.com/ghostty-org/ghostty/pull/8254 to allow
middle click + TrackPoint scrolling on MacOS. `primary-paste` naming
comes from `gtk_enable_primary_paste`.
The following configuration values for `middle-click-action` are
provided:
- `primary-paste` - Paste from the selection (or system) clipboard per
`copy-on-select`.
- `ignore` - Do nothing, ignore the middle click.
Tested locally on macOS with Zig 0.15.2 using `zig build
-Doptimize=ReleaseFast`.
Thank you!