Prevent saved CHOAM movement arrival deadlocks

Preflight ordinary movement through the existing arrival quote before creating new Ornithopter escrow or opening Ixian, Fremen and CHOAM prevention windows. An explicit legacy CHOAM decline can return an uncommitted unsupported arrival for another choice without consuming movement or touching forces, spice, cards or tokens. Preserve an existing Ornithopter and retire it exactly once on a legal replacement move. Keep dedicated Ambassador relocation handling and Karama cancellation validation before cost; unrelated exceptions remain atomic. Simultaneous Ambassador/Terror priority still awaits the recorded material interpretation, with no invented ordering.

Add reusable offline faction-game samples with genuine Basic/Advanced setup, all four AI profiles, physical custody checks, JSON restorations, private traces and failed snapshots. Source-bound reports and input snapshot hashes make fresh and resumed samples repeatable; document that a resumed continuation starts a new seeded stream and does not prove input setup provenance.

Validation: independently reviewed fresh declaration, native cancellation, supported single arrivals, legacy retry and card custody tests. Two production SQLite tests cover authenticated private restoration, stale/duplicate/wrong-owner rejection, resource conservation and concurrent version races. Typecheck, lint, 4583 offline tests, production build and 43 HTTP tests passed. Retain the initial failed check log for the corrected numeric-sort lint issue.

All six fresh samples complete. CHOAM Basic 1054 actions/28 JSON restores, CHOAM Advanced 225/6, Ecaz Basic 91/2, Ecaz Advanced 523/14, all-three Basic 476/12, all-three Advanced 1303/35 with a turn-six CHOAM win. Combined Advanced has 46 guarded arrival candidates with legal alternatives. The exact prior 614-action failed snapshot separately finishes after 691 additional actions/18 restores and 39 guarded candidates. These are bounded paths, not complete faction or combination certification. Gameplay source hashes match the final checkpoint; later evidence-only documentation and recovery-test lint edits are explicit.

After the reported outage, all 632 opening games and original seat/recovery records were preserved (665 after HTTP tests); integrity and foreign keys passed. Existing Ecaz and Ixian browser seats restored their same private hands, resources and pending choices after reload. This is browser restoration evidence, not a staged arrival-return claim. The healthy server was reused; no restart, database reset, recurring automation or publication.

Verified source tree: 550221850f4802c41155f7bbc35d623965bc7db3330825636d50f26bb42868f8

docs/RULE_DECISIONS.md

@@ -35,6 +35,7 @@ These are unresolved in the cited records. Do not infer an answer from elapsed t
 
 | Boundary | Still unresolved | Existing record |
 | --- | --- | --- |
+| Ambassador/Terror arrival priority | Both optionally react to the same entry, but no publisher/designer priority was found. The order can change Fremen relocation versus Atomics losses. A user question has been sent: keep the overlap gated pending an official ruling, or use explicitly provisional storm order. No answer is assumed; Baliset remains a separate pre-entry prevention effect. | [Reproduction and source boundary](DEFERRED_MOVEMENT_ARRIVAL.md) |
 | Sapho remaining timing | First versus unspent Advanced Guild priority, partly completed combined turns, cyclic auction duration and remaining battle timing stay guarded. Prior questions remain unanswered. | [Source audit](JUICE_OF_SAPHO_SOURCE_UPDATE.md), [battle review](JUICE_OF_SAPHO_BATTLE_REVIEW.md) |
 | Mirror Weapon | Whether copied Tooth/Artillery mandatory-discard rules attach to the physical Mirror remains unanswered; arithmetic helpers do not admit the full battle card. | [Engine audit](MIRROR_WEAPON_ENGINE_AUDIT.md) |
 | Semuta Drug | Full-hand take-before-discard and the privacy-neutral immediate reaction protocol remain unresolved. Typed discard continuations already exist; they are not activation. | [Source update](SEMUTA_SOURCE_UPDATE_20260907.md), [privacy review](SEMUTA_PRIVACY_REVIEW.md) |