Ask which side of the confidence threshold a delete of every listed type reaches

[mattdawkins]

• When every type shown in the type list is selected and the delete button is pressed, a dialog now asks whether to delete tracks above the current confidence threshold (what the list shows, the previous behaviour), below it (the tracks the list hides), or all of them regardless of threshold. Partial selections and the group list keep the plain confirmation.

• BaseFilterControls.removeTypeAnnotationsByThreshold(types, scope): above delegates to the existing visible-list removal; below/all walk every annotation and remove the type only where its confidence is under that type's threshold, or everywhere, deleting the track when no type remains.

• Unit tests for the three scopes and for the dialog gating; docs updated.

• Follow-up: the track list's delete button (sidebar and bottom bar) asks the same question when every listed track is checked — above = the listed tracks, below = tracks of the enabled types hidden by the thresholds, all = both. The dialog moved into a shared DeleteAllScopeDialog; spec added.

🤖 Generated with Claude Code

[mattdawkins]

Superseded by #1944: the question belongs on the track list, not the type list.