docs(builder): crew#139 is an open proposal, and the CI cost is what it would end

Both occurrences said crew's engine already converts a PR back to draft at
round close; crew#139 is OPEN, blocked and unassigned, so the passage was
describing an unshipped mechanism as live (codex, kimi). The same sentence
also read as if the conversion caused the CI spend — it is the status quo
the conversion would end, so the counterfactual is now explicit. Rewrapped
the paragraph at 80 columns; 7948b99 had left one line at 133.

BUILDER.md

@@ -298,23 +298,27 @@ CONTRIBUTING; the shared flow lives here and is not restated there.)
    ([#50 D11](https://github.com/heavy-duty/ceremony/issues/50)).
 
 **A fix round may ride a draft.** An engine may convert a PR back to draft
-when a round closes, and crew#139's does: where an engine's own rules make a
+when a round closes; crew#139 proposes exactly that, and is still an open
-builder's mid-round pushes *saves* rather than proposals, every save fires CI
+proposal. What it names is the status quo without it: where an engine's own
-— 41 of 106 commits across crew's last 25 PRs, by that issue's measurement. Ceremony implements no such conversion and this passage
+rules make a builder's mid-round pushes *saves* rather than proposals, every
-specifies none; it is written down because a builder or a reviewer who meets a
+one of those saves fires CI while the PR sits ready — 41 of 106 commits
-mid-round draft has to find a state the doctrine describes. What it means is
+across crew's last 25 PRs, by that issue's measurement — and converting back
-what a draft already meant while you were building, extended and not changed:
+to draft is what would stop them. Ceremony implements no such conversion and
-the draft phase is yours and the panel cannot see it (Building, above). Whose
+this passage specifies none; it is written down because a builder or a
-ball it is does not change either — the round outranks the draft, so you still
+reviewer who meets a mid-round draft has to find a state the doctrine
-owe it whole, the fixes and the reply and the flip. The label axis says the
+describes. What it means is what a draft already meant while you were
-same thing in the machine's voice rather than in this one, and
+building, extended and not changed: the draft phase is yours and the panel
-[LABELS.md](LABELS.md)'s `state:building` row is where to read it (#205).
+cannot see it (Building, above). Whose ball it is does not change either —
+the round outranks the draft, so you still owe it whole, the fixes and the
+reply and the flip. The label axis says the same thing in the machine's
+voice rather than in this one, and [LABELS.md](LABELS.md)'s `state:building`
+row is where to read it (#205).
 
 **Ready-for-review is the act that ends the round, and it is the builder's
 alone.** No engine marks a PR ready. The flip asserts that the round was
 answered whole, and that assertion is the one judgement about a round its
-author cannot delegate to a machine: an engine may draft a PR, and crew#139's
+author cannot delegate to a machine: an engine may draft a PR, which is what
-does, but only the builder undrafts it.
+crew#139 proposes engines do, but only the builder undrafts it.
 
 **Where a draft suppressed the checks, green is proven at the flip and the
 request still follows it.** Step 1's precondition is the whole rule and this