ci(image): keep Claude Code 2.1.251; test(ceo-mode-routing): keep HOLD's own deferrals in scope before assessing its rigor decision

2.1.284 enables per-turn effort for claude-fable-5-1: in gate census
36626737820, 66 of 84 sessions ran longer than on 2.1.251 (+20% session time,
+32% thinking tokens) and 11 cases timed out on unchanged budgets.

HOLD SCOPE's 0G step asks its own defer/keep menu; the actor answered it
Defer and the assessment then judged that scope question as the rigor
decision. The actor now answers that menu Keep and assesses the next one.

CHANGELOG.md

@@ -30,7 +30,6 @@ Run `bun run typecheck` and `bun run typecheck:test` before you push; both are f
 #### Fixed
 - `$B connect --supervise` respawned with a block-scoped env that no longer existed, so every restart threw and the supervisor gave up after five tries. The headed env is one helper used by connect and respawn, and the loop has behavioral tests.
 - Compiled `/cso` installs called an unimported `join` when launching the assertion-witness child, breaking runtime-tested witnessing for every installed user.
-- The CI image pins Claude Code 2.1.284, which recognizes the default eval model; 2.1.251 logged `unrecognized_model` and stalled mid-stream.
 - `/review` workflow ambiguities (smoke clock vs required revalidation, setup authority, plan-completion gate, findings record), `/office-hours` builder mode not loading its brainstorm section, `/sync-gbrain` Step 4 helper arguments and write path, `/plan-ceo-review` expansion framing and pacing menus, `/plan-design-review` with no designer API key, and `/deslop-shared-libs` one-file-per-turn reads.
 - Eval detectors that graded wording or step order now grade outcomes: eng batching, CEO split-overflow, mode routing, section-loading stale-fill, outside-voice-disabled attribution, design focus menus, and PTY permission dialogs with cropped titles.