* fix: include buttons bitmask in drag mouseMoved events
The drag handler was omitting the `buttons` field from every
`mouseMoved` event dispatched during the move phase. Without it the
browser sees `event.buttons === 0`, meaning no button is held, so
`dragstart`/`dragover`/`drop` never fire and the drop target never
receives the element.
Fix:
- Add `"buttons": 1` (left-button mask) to each `mouseMoved` sent
while the button is held.
- Add `"buttons": 1` to `mousePressed` and `"buttons": 0` to
`mouseReleased`, consistent with how `dispatch_click` handles the
same fields in interaction.rs.
- Correct the parity-test fixture for `drag`, which was supplying a
`selector` key instead of the `source` key that `handle_drag` reads.
- Add an e2e test (`e2e_drag_action_sends_buttons_during_move`) that
drives the high-level `drag` action against the existing
`html5_drag_probe` fixture and asserts that `mousemove` events carry
`buttons == 1` and that `dragstart` fires on the source element.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* style: fix rustfmt formatting in e2e drag test
---------
Co-authored-by: wangjingjing <wangjingjing.99@bytedance.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: ctate <366502+ctate@users.noreply.github.com>
