Connect genuine Ix expansion setup to playable prototypes

Add an offline Ix initializer through the real setup pipeline, supporting Basic
and Advanced play, base factions, Ixians and Tleilaxu with the full 47-card deck
and 22-card spice deck. Preserve all normal start and publication gates.

Add a reusable local prototype starter: back up the named fresh ready lobby,
initialize it once by exact version/state comparison and preserve seat/recovery
tables and other rooms. Update the existing checklist with a separate prototype
stage and document functional scope, source interpretations and later refinement.

Six new tests cover all-profile private setup, exact typed starting forces,
Face Dancer/treachery custody, JSON continuation, two fixed-seed complete games
and local SQLite write/rejection boundaries. Independent review caught a missing
JSON version update, now fixed and covered; focused checking fixed one test typing
error before the stable broad check. No new rule interpretation was introduced.

Validation: types, lint and 4,211 offline tests passed (123.237s); production build
passed (6.543s); all 40 HTTP tests passed (23.578s). Source-bound report:
20260913-ix-prototype-final/report.json, fingerprint
3b8f295593bcb314bb72308d81739006b11d949d1e5906dbf6ce0704b15ebd72.

Browser W5LE6VFB: human Ixian + Medium Tleilaxu + Hard Atreides from genuine
setup, private starting-card refresh, Weather Control, mobile stronghold placement,
then owned Brutal autopilot. Atreides won on turn 1; this short complete journey
is not proof of every card or faction interaction. Finished private hand restored
at phone width; expanded Poison Tooth was readable. Fixed-seed offline games
2026091301 (Basic) and 2026091302 (Advanced) both completed with both Ix factions.

All 64 opening room versions/hashes are unchanged. One browser room and 30 HTTP
rooms were added, totaling 95. Reused the running server; no restart or automation.

Aggregate goal counters: 59,524,858 to 59,976,567 at completed verification,
451,709 tokens before final Git overhead. Two bounded workhorse helpers handled
inventory/tests and independent review; one stable full check/build/HTTP run.
Full game scope remains active and unfinished; future work prioritizes missing
functional prototypes before exhaustive refinement and final acceptance.

game/engine.ts

@@ -4919,7 +4919,14 @@ export function initializeNexusGameForAudit(state: Game): Game {
     'Enable Nexus cards in a fresh audit lobby first.');
   return initializeSetupGameForAudit(state, !!state.homeworlds, true);
 }
-function initializeSetupGameForAudit(state: Game, homeworlds: boolean, nexus = false): Game {
+/** Offline prototype entry through real Ix setup, including both expansion factions.
+ * No player action or room API bypasses the normal release gates. */
+export function initializeIxGameForAudit(state: Game): Game {
+  requireRule(state.expansions.length === 1 && state.expansions[0] === 'ix',
+    'The Ix prototype requires exactly the Ixians & Tleilaxu expansion.');
+  return initializeSetupGameForAudit(state, false, false, true);
+}
+function initializeSetupGameForAudit(state: Game, homeworlds: boolean, nexus = false, ix = false): Game {
   nexusCardsIntegrity(state);
   homeworldRule(() => homeworldGameIntegrity(state));
   homeworldBattleLossIntegrity(state);
@@ -4941,17 +4948,19 @@ function initializeSetupGameForAudit(state: Game, homeworlds: boolean, nexus = f
     'The audit initializer requires two through six distinct ready players and an existing host.',
   );
   requireRule(
-    (homeworlds || nexus || g.expansions.length === 0) &&
+    (homeworlds || nexus || ix || g.expansions.length === 0) &&
       (nexus || !g.nexusCards) &&
       !g.techTokens &&
       !g.strongholdCards &&
       (homeworlds || !g.homeworlds) &&
       g.players.every((p) =>
         FACTIONS.some(
-          (f) => f.id === p.faction && (homeworlds || nexus || f.expansion === 'base'),
+          (f) => f.id === p.faction && (homeworlds || nexus || f.expansion === 'base' || (ix && f.expansion === 'ix')),
         ),
       ),
-    homeworlds
+    ix
+      ? 'The Ix prototype supports base, Ixian and Tleilaxu factions without optional modules.'
+      : homeworlds
       ? 'The Homeworld setup audit supports implemented deck sets without Tech Tokens or Stronghold Cards.'
       : 'The audit initializer supports base factions without expansions or optional modules.',
   );
@@ -4979,7 +4988,7 @@ function initializeSetupGameForAudit(state: Game, homeworlds: boolean, nexus = f
           !p.prediction &&
           !p.advisorSetup &&
           (!p.elites ||
-            ((homeworlds || nexus) &&
+            ((homeworlds || nexus || ix) &&
               p.faction === 'ixians' &&
               p.elites.reserves === 7 &&
               p.elites.tanks === 0 &&