Pair simulator pointer gestures before replacing the active gesture #545

SimulatorScreen forwards streamed down/move/up gestures but stores only one active pointer. Another pointer-down replaces pressRef without first ending the previous gesture; later up/cancel for the previous pointer is ignored. Its unmount cleanup releases frame/mask resources but does not explicitly end an active pointer gesture. A synthetic wheel gesture can also remain pending when a pointer gesture starts, and its idle callback sends a touch-up without owning the newer gesture.

The native consumer makes the ownership problem concrete: interactive::touch allocates a fresh HID identifier on down and replaces the per-device map entry without sending an up for the old identifier; a later up removes/releases only the currently mapped identifier. Pinch has the corresponding two-identifier lifetime. Thus an earlier injected touch can be left unmatched in the guest; this does not mean its old identifier remains retrievable in the daemon/sidecar map.

Finish the owned gesture before replacement/unmount, using its original device/callback, touch-or-pinch mode and last coordinates; settle wheel ownership before starting a pointer gesture, preserving normal cancel and pinch semantics. Source reassessment at master 22c337f only. No macOS/CoreSimulator gesture run or stuck-input duration has been measured in this reassessment.