NOTHING_TO_RETIRE

DEFAULT with the retirement floor at zero — for a binding whose alphabet declares no OpKind.RETIRE op because the type has nothing to retire.

Named for the claim rather than for a shape, because the bindings that qualify are not all the same shape. GSet, GCounter, PNCounter and IntMax genuinely only grow, and DotContext only records dots it has seen. But MVRegister supersedes — set drops the values it causally dominates — and BoundedCounter's spend and transfer consume quota by adding to grow-only tallies. Neither grows in the naive sense; both qualify under the test at the top of OpKind, and each binding argues it where it declares this.

Reach for it only when a retiring op could not be written. A binding that could retire and does not is the vacuity shape itself, not a candidate for a waiver: LWWMap sat at 0.0% retiring steps for as long as it had a binding, with LWWMap.remove in the type the entire time. That wanted the op, which is what it got.