Connect Emperor Nexus extra revival with private saved continuation

Add the absent-Emperor Secret Ally alternative returning exactly three eligible forces free in Basic/Advanced base-faction Nexus games. Preserve ordinary force/free-revival allowances and the shared Advanced Fedaykin cap. Keep the action optional and private, consume the physical Nexus once, and validate durable source receipts through later ordinary revival and Ghola. Purchase timing remains pending the earlier uniform winner-payment UX question; partial returns and combined-module interactions remain guarded. No mode or publication gate opens.

Connect private controls, explicit physical elite selection, all four legal AI profiles and a dedicated rules checklist entry. Extend the reusable local prototype writer with genuine twelve-card Nexus setup. Independent review covers rules timing, private projection, physical custody, JSON and production SQLite restore, lost-response replay and competing requests. Seventeen focused effect cases and four prototype-writer cases pass.

Validation: typecheck, lint, 4649 offline tests, production build and 43 HTTP tests passed with unchanged source. Genuine-start Basic and Advanced samples completed in 715 and 263 actions with 19 and 7 periodic JSON restores, respectively, and no Emperor uses. Two explicitly staged continuations completed in 18 and 17 actions with one normal-force Emperor return each. All four had zero rejections and preserved exact Treachery, force, elite and Nexus custody; all fourteen final seat views restored unchanged. They are bounded continuation evidence, not natural full-game acceptance of the effect or AI calibration.

In the conserved staged browser scenario, Advanced Fremen returned three forces including one Fedaykin using the Nexus, then three normal forces using the ordinary allowance. Reserves rose from three to nine, Tanks fell from seven to one, spice stayed three and the physical Nexus was spent once. The inspector was readable, the action notice displayed, and pending/resolved refresh restoration, physical custody and private projection passed.

After the reported power outage, all 733 opening games and original seat/recovery records were preserved (767 after HTTP checks); database integrity and foreign keys passed. All 734 rooms immediately before broad verification remained unchanged. Reused the healthy server without restart, reset or recurring automation.

Verified source tree: fd09a4bc71018cb7ef98c7e25c25dacc495ffed304dbd0cdfa223e539e8fa5e1

docs/RULE_DECISIONS.md

@@ -52,6 +52,7 @@ These are unresolved in the cited records. Do not infer an answer from elapsed t
 | 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) |
+| Emperor Secret Ally purchase timing | The purchase choice follows winning the bid. A holder-only payment pause exposes concealed card eligibility, while per-bid preauthorization moves the choice earlier. The user has been asked whether to permit a uniform winner payment confirmation, including sole spice payments, or retain the purchase gate. No answer is assumed; the independent three-force revival grant can proceed. | [Purchase source contract](NEXUS_EMPEROR_RULES.md#secret-ally-retain-the-actual-purchase-price) |
 | 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 |