Not a style finding. `onToggleItem` was added to BoardScreen's signature and read
inside NoteBoard — which is a separate top-level composable, not a nested one, so
the two were never connected. detekt reported it as an unused parameter; the
compiler would have called it an unresolved reference. Neither had run: Kotlin is
compiled at the "Unit tests" step, which is gated behind detekt, so nothing in this
lane had type-checked the Android changes yet.
Threaded properly now, which is what makes ticking a box from the board actually
work rather than merely appear to.
Two more from reading it again with that in mind:
* `when { item != null -> … onToggleItem(index, …) }` would not have compiled.
Kotlin does not infer that a non-null item implies a non-null index, so the
index stayed `Int?` against an `Int` parameter. Both are in the condition now.
* continueChecklist had six returns against detekt's limit of two. Collapsed to
one `when`, with the two intermediate values guarded on `typedNewline` —
`caret - 1` is only a real index once it is known to be the newline just typed.