[AmethystLiang]

Summary

• The "Don't ask again" label and unchecked checkbox border in the delete worktree dialog were rendered with text-muted-foreground / border-muted-foreground/50, which is too faint to see against the dialog background.
• Bumped the label to text-foreground/80 and the unchecked border to border-muted-foreground so the control is clearly visible at rest while preserving the checked and hover styling.

Test plan

• Open the delete worktree confirmation dialog; verify the "Don't ask again" label and checkbox are clearly legible in both light and dark mode.
• Hover the control — label still brightens to text-foreground.
• Toggle the checkbox — checked state still renders filled.