Add sync toggle and opposite-view ROI outline

[SomeKindOfDuck]

This is a small GUI improvement for manual ROI curation. I kept the change optional and tried to preserve the existing behavior when the sync toggle is disabled.

Summary

This PR improves manual ROI curation in the GUI by adding an optional sync toggle for the cell and not-cell views.

When enabled, panning and zooming in one ROI view updates the other view. The selected ROI is also shown as an outline in the opposite view, which makes it easier to compare corresponding cell and not-cell regions.

Changes

• Add a sync views checkbox near the ROI view controls.
• Synchronize cell and not-cell view ranges only when the checkbox is enabled.
• Show the selected ROI outline in the opposite view.
• Clear the selected outline after right-click cell/not-cell reassignment.

Tests

• python -m compileall suite2p/gui
• pytest -vs
  • 25 passed, 24 warnings

The warnings appear to come from existing dependencies or unrelated non-GUI modules.

Manual checks

• Loaded suite2p output in the GUI.
• Confirmed sync on/off behavior in both view.
• Confirmed selected ROI outlines appear in the opposite view.
• Confirmed right-click reassignment clears the selected outline.