`toggle_at` existed to map a tap on `[ ]` inside a plain text field to an item, and `continuation` to make Return start the next one. The block editor needs neither: a checkbox is a real Checkbox, so it is tapped rather than located, and Return is the field's own IME action rather than a shape recognised in a string. Removed rather than kept for later (rule 22). Both were exported over the FFI with no Kotlin caller, which is API surface promising something nothing does — and their tests were weight on code nothing runs. The section comment above them described the tap-in-a-text-field problem, which is no longer the problem this pair solves. Rewritten to say what is actually there: one function to read a body apart, one to put a line back together, and between them Kotlin renders checkboxes without owning the grammar.