feat: support cross-origin iframe snapshots and interactions via Target.setAutoAttach (#949)
* feat: support cross-origin iframe snapshots and interactions via Target.setAutoAttach (#925)
Enable Target.setAutoAttach with flatten: true on page sessions so Chrome
auto-creates dedicated CDP sessions for cross-origin iframe targets.
- Add DrainedEvents struct, iframe_sessions map, attach/detach event handling
- Extract resolve_ax_session (shared) and resolve_frame_session helpers
- resolve_element_object_id returns (object_id, effective_session) tuple
- resolve_element_center returns (x, y, effective_session) tuple
- Input dispatch (click/hover/tap) uses effective session for correct coordinates
- Thread iframe_sessions through element.rs, interaction.rs, screenshot.rs
- Clear iframe sessions on navigate, tab switch, tab new, tab close
- Ignore Target.setAutoAttach failure for non-Chrome backends (Lightpanda)
- Unit tests for session resolution logic
* fix
* fix
* fix
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Co-authored-by: hyunjinee <leehj0110@kakao.com>
