C-320: a budget cut performs exit bookkeeping — exhausted is always Err, regions independent, placement unobservable (ALS-DT2)

[O6lvl4]

Adjudication of greenfield's stage-64 finding, taken under the delegated judgment (as with #28/#29). Requirements-first, since = 0.60.0 (tightened to a 0.59.x release if the maintenance line repairs it first — it is squarely リーク修理).

Ruling (ALS-DT2, "cut の簿記"): a fan.bounded cut runs the same meter bookkeeping as a normal region exit. Therefore (1) exhausted ⇒ Err, never a stale Ok; (2) regions are independent — meter state cannot leak between regions; (3) cut placement (direct-in-arm loop vs callee) and loop form are unobservable; (4) the meter charges the budgeted body only — runtime services (formatting, the ?? fallback) are never metered or cut.

Measured on 0.58.0 (fixture fuel_cut_in_arm_loop.almd, both targets byte-identical — the co-drift class agreement cannot see): expected 6 6 -1 -1 6 6 -1 6 -1, actual 6 6 -1 -1 6 6 0 0 0 — a direct-arm cut returns stale ok(0) and poisons every later region, roomy or exhausted alike; callee-loop cuts are correct, which is why the pre-existing fuel fixtures stayed green. Filed as almide/almide#1572. The reference leg pins the values once the evaluator meters fan.bounded (its abstain ledger carries the class, 88 → 89, solo ratchet commit per the separation rule).

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