Arcsphere "Remove Sphere" UX Issues

- Lack of Deletion Countdown
- Issue: When selecting a sphere and clicking "— Remove", there is no safety countdown.
- Problem: The action is executed immediately, which can lead to accidental deletion of spheres and their associated data.
- No "Undo" Capability
- Issue: Once a sphere is removed, there is no "Undo" snackbar or option to restore the sphere.
- Problem: The deletion appears to be permanent with no immediate way to recover the Arcsphere state if the button was clicked by mistake.
- Safety Risk
- Observation: The "Remove" button is located very close to the central interaction area (as seen in the screenshot), increasing the likelihood of accidental taps.