Prototype voluntary seat handover with durable private retries

Let a current owner issue, cancel or replace a private 24-hour one-time offer.
Recipients accept the same faction and saved game while old browser sessions,
recovery keys and entry receipts lose authority. Preserve exact claim retries
across refresh, restart and later offers, with private tab-scoped continuation.

Fence every claim mutation to its winning transaction. Add durable receipts
and additive backfill for already-issued offers without changing game JSON or
existing seat authority. Block competing navigation during unresolved owner
operations; remove invalidated owner kits on confirmed recovery.

Record the pending CHOAM Nexus after-victory secrecy/window decision without
inventing the unresolved gameplay or opening mode/publication gates.

Validation: types/lint and 4,364 offline tests passed; production build passed;
43 HTTP tests passed. Added 19 offline and 3 HTTP regressions. Independent
privacy/persistence review passed, including deterministic CAS interleavings,
rollback, legacy migration and exact receipt restoration. Browser room 2EMYG4CY
retained private setup choices after handover/refresh and continued into Storm;
follow-up recovery removed its invalid offer with cards/forces/spice unchanged.
All 218 opening rooms preserved (291 after QA and both broad runs). The opening
456 seat, 49 recovery-key, 56 recovery-receipt and 106 entry-receipt rows were
also verified unchanged. Server reused; no restart or recurring automation.

Final private report: ~/.local/share/dune/checkpoints/20260913-seat-handover/
verification-final/report.json. Source fingerprint:
8949cdf58eb8bc8bd33f2657c6b21352b3ee5e17e2a556c684a89073015632f4.
Check/build/HTTP duration: 140565/6689/24835 ms. The earlier broad run passed;
a final recovery-UI review fix required the second source-bound run.
Goal aggregate counter 64,301,976 -> 65,031,751 before Git (729,775) for this
bounded capability and its concurrency/recovery review; full goal remains active.

docs/RULE_DECISIONS.md

@@ -34,6 +34,7 @@ These are unresolved in the cited records. Do not infer an answer from elapsed t
 | Orgiz collection | User question pending: take one spice per positive board pile collected, or leave the effect pending? The publisher does not clarify stacked Spice Blows. The draft quote remains opt-in and is not enabled by the engine. Contested Cistern income also remains outside the ordinary sole-occupant prototype. | [Discovery interpretations](DISCOVERY_PROTOTYPE.md#interpretations-retained-for-refinement) |
 | Jacurutu physical dial | The user question asks whether the losing player should choose the physical normal/elite forces represented by its dial. When legal Advanced allocations produce different rewards, income remains explicitly unpaid; numeric wheel subtraction is not a ruling. | [Discovery interpretations](DISCOVERY_PROTOTYPE.md#interpretations-retained-for-refinement) |
 | Testing Station contest/timing | Only sole non-advisor occupation is prototyped. Two-occupant priority/stacking remains unresolved; opening after the ordinary storm-card window is an explicit source-timing inference. Weather Control is excluded by the printed text. | [Discovery interpretations](DISCOVERY_PROTOTYPE.md#interpretations-retained-for-refinement) |
+| CHOAM Secret Ally battle timing | The printed after-victory inspection is optional and the Nexus identity stays secret. No existing postbattle choice covers every winner: a pause only for a holder leaks ownership, precommitment removes the after-win choice, and a universal window makes nonholders pass. The product-exception question has been sent; no timing policy is implemented pending the answer. Ordinary Karama cancellation is also not established by the retrieved sources. | [After-victory inspection audit](NEXUS_CHOAM_SECRET_ALLY.md#after-victory-inspection-audit) |
 | Discovery prototype inferences | Free entry uses storm order and ordinary source-storm restrictions; these are general-rule inferences. Great Maker currently follows ordinary first-turn worm skipping and Sandtrout suppression; an exhausted token type creates no replacement token. These preserve current source interpretation and physical inventory but are not separately confirmed rulings or complete combined-module certification. | [Interpretations for refinement](DISCOVERY_PROTOTYPE.md#interpretations-retained-for-refinement) |
 | Other Homeworld combinations | Population/force splitting, removal custody, replacement shortages, income accounting and placement ordering remain local to their detailed contracts. | [Homeworld rules](HOMEWORLD_RULES.md), [occupation](HOMEWORLD_OCCUPATION_RULES.md) and the effect documents above |