Expose an explicitly unfinished Advanced preview in normal lobbies

Add room-creation and host lobby rules selectors, readiness reset, explicit
preview start and a persistent warning. Admit the six classic factions,
Tech Tokens with 3+ players and optional Stronghold Cards through genuine
setup. Keep expansion/module gates and complete-rules/publication criteria.

Persist the preview marker and enforce fresh native leaders, unchanged
piece custody and clean runtime/pacing state. Preserve private projections,
JSON continuation, exact room-entry retries and version/CAS protection.
Independent review resolved malformed leader, extra card-zone, missing
required-key and stale bot-deadline admission gaps.

Validation on the shared development tree: types, lint, 5169 offline
tests, build and 50 HTTP tests passed. The tree also contained the
separate deployment task's changes; this commit stages only preview scope.
All 57 base rosters completed real setup with each legal AI profile. Five
normal-preview-start games (2–6 seats) completed 1950 actions and
51 JSON restores without rejected actions; no strategy calibration.

Browser: actual create, host switch/readiness/Stronghold reset, explicit
start, exact private refresh, desktop and mobile warning checked. Retained
dev process stopped; backed up 1,629 saved games, restored server with all
unchanged, and resumed the same traitor choice into Storm. Baseline all-table
preservation retained 1626 rooms and 3442 seats; totals
now 1669 rooms and 3536 seats. No reset or automation.

Preview remains incomplete. Legacy unsupported expansion creation payloads
remain accepted for exact retry compatibility but cannot start. Existing
rules ambiguities and full visual acceptance remain open.

game/engine.ts

@@ -1554,6 +1554,8 @@ export type Game = {
   mentatHistory?: MentatObservation[];
   mentatHistoryEvents?: string[];
   advanced: boolean;
+  /** Explicit normal-lobby opt-in; unfinished rules remain labeled as a preview. */
+  advancedPreview?: true;
   expansions: string[];
   players: Player[];
   /** Fixed printed player circles; absent only in rooms created before this rule fix. */
@@ -5082,26 +5084,93 @@ function takeBattleLosses(g: Game, p: Player, t: string, losses: Casualties) {
   );
   return lostCyborgs;
 }
-function start(g: Game) {
+function baseStartProfileBlock(g: Game): string | null {
+  if (g.homeworlds) return 'Homeworld gameplay is still being implemented.';
+  if (g.nexusCards) return 'Nexus card effects are still being implemented.';
+  if (g.discoveryEnabled || g.discoveries || g.discoveryStash || g.greatMaker)
+    return 'Discoveries are still being implemented.';
+  if (g.leaderSkills) return 'Leader Skills are still being implemented.';
+  if (g.ecazTreachery) return 'Ecaz Treachery Cards are still being implemented.';
+  if (g.mentatQuestionPreview || g.moritaniAssassinatePreview || g.moritaniAssassinate)
+    return 'Separate development profiles cannot be enabled by a normal start.';
+  if (!g.players.every(p => FACTIONS.some(entry => entry.id === p.faction && entry.expansion === 'base')))
+    return 'Expansion factions are still being implemented.';
+  if (g.expansions.length !== 0) return 'Expansion rules are still being implemented.';
+  return null;
+}
+function advancedPreviewIntegrity(g: Game) {
+  if (g.advancedPreview === undefined) return;
+  requireRule(g.advancedPreview === true && g.advanced === true && g.status !== 'lobby' && !baseStartProfileBlock(g),
+    'The saved Advanced preview no longer matches its supported rules profile.');
+}
+function requireFreshSetup(g: Game, allowIxElites = false) {
+  requireRule(g.status === 'lobby' && !g.setupStage && g.turn === 1 && g.phase === 0 && g.advancedPreview === undefined,
+    'Start only from a fresh lobby.');
+  requireRule(g.players.length >= 2 && g.players.length <= 6 &&
+    new Set(g.players.map(p => p.id)).size === g.players.length &&
+    new Set(g.players.map(p => p.faction)).size === g.players.length &&
+    g.players.some(p => p.id === g.host) && g.players.every(p => p.id && p.ready),
+  'Start requires two through six distinct ready players and an existing host.');
+  requireRule(!g.deck.length && !g.discard.length && !g.spiceDeck.length &&
+    !g.spiceDiscard.some(pile => pile.length) && !g.traitorReserve?.length &&
+    g.ecazLoyalty === undefined && !g.decision && !g.response && !g.battle && !g.winner.length &&
+    g.players.every(p => !p.hand.length && !p.traitors.length && !p.traitorChoices.length &&
+      Object.keys(p.forces).length === 0 && p.reserves === 20 && p.tanks === 0 && p.spice === 0 &&
+      p.moved === 0 && !p.shipped && !p.prediction && !p.advisorSetup &&
+      (!p.elites || (allowIxElites && p.faction === 'ixians' && p.elites.reserves === 7 &&
+        p.elites.tanks === 0 && p.elites.revived === 0 && Object.keys(p.elites.forces).length === 0))),
+  'Starting setup cannot redeal or replace existing game pieces.');
+  requireRule(g.players.every(p => {
+    const native = leaders(p.faction);
+    return p.leaders.length === native.length && native.every(expected => {
+      const actual = p.leaders.find(leader => leader.id === expected.id);
+      return actual && Object.keys(actual).length === Object.keys(expected).length &&
+        Object.entries(expected).every(([key, value]) => actual[key as keyof Leader] === value);
+    }) && p.ally === null && p.allySinceTurn === undefined && p.bribes === 0 && p.revived === 0 &&
+      (p.freeForcesRevived ?? 0) === 0 && p.leaderRevived === false && p.revivalCycle === 0 && p.battleLosses === 0 &&
+      !p.specialKaramaUsed && p.kwisatz === undefined && p.charityTurn === undefined &&
+      p.noField === undefined && p.noFieldEvent === undefined && p.noFieldBlockedTurn === undefined &&
+      p.advisors === undefined && p.gholaBlocked === undefined && p.ixMovementBlocked === undefined &&
+      p.fremenMovementBlocked === undefined && p.faceDancers === undefined &&
+      p.faceDancerReplacedTurn === undefined && p.revealedTraitors === undefined;
+  }), 'Starting setup requires unused native leaders and no prior alliance, revival or battle history.');
+  requireRule(Object.keys(g.playerPositions ?? {}).every(id => g.players.some(p => p.id === id)),
+    'Player circles must belong to seated players.');
+  normalizedPlayerPositions(g);
+}
+function requireFreshBaseRuntime(g: Game) {
+  requireRule((g.botsPending === undefined || g.botsPending === false) && g.botNextActionAt === undefined,
+    'Start with no pending bot work or prior action deadline.');
+  const fresh = createGame(g.code, getPlayer(g, g.host), g.advanced);
+  // These are the live lobby settings and storage metadata. Module admission and
+  // unowned optional components are checked separately; gameplay fields stay fresh.
+  const configuration = new Set<keyof Game>(['code', 'version', 'host', 'players', 'playerPositions',
+    'advanced', 'expansions', 'log', 'botsPending', 'botNextActionAt', 'techTokens', 'strongholdCards',
+    'homeworlds', 'nexusCards', 'discoveryEnabled', 'leaderSkills', 'ecazTreachery']);
+  const keys = [...new Set([...Object.keys(g), ...Object.keys(fresh)])] as (keyof Game)[];
+  requireRule(keys.every(key => configuration.has(key) ||
+    JSON.stringify(g[key]) === JSON.stringify(fresh[key])),
+  'Starting a base table cannot retain existing game resources, histories or continuations.');
+}
+function start(g: Game, advancedPreview = false) {
   requireRule(g.players.length >= 2, 'At least two players are needed.');
   requireRule(
     g.players.every((p) => p.ready),
     'Every player must be ready.',
   );
-  requireRule(!g.advanced, 'Advanced rules are still being implemented.');
-  requireRule(!g.homeworlds, 'Homeworld gameplay is still being implemented.');
-  requireRule(!g.nexusCards, 'Nexus card effects are still being implemented.');
-  requireRule(!g.discoveryEnabled, 'Discoveries are still being implemented.');
-  requireRule(!g.leaderSkills, 'Leader Skills are still being implemented.');
-  requireRule(
-    g.players.every((p) => faction(p.faction).expansion === 'base'),
-    'Expansion factions are still being implemented.',
-  );
-  requireRule(
-    g.expansions.length === 0,
-    'Expansion rules are still being implemented.',
-  );
+  requireRule(typeof g.advanced === 'boolean' && (!g.advanced || advancedPreview),
+    'Advanced rules are unfinished. Explicitly choose Start Advanced preview to continue.');
+  requireRule(!advancedPreview || g.advanced, 'Choose Advanced preview rules before starting that preview.');
+  const blocked = baseStartProfileBlock(g);
+  requireRule(!blocked, blocked ?? 'This rules profile is unavailable.');
+  requireFreshSetup(g);
+  requireRule(!g.techTokens || JSON.stringify(g.techTokens) === JSON.stringify(createTechTokens()),
+    'Start with unused Tech Tokens before assigning their initial owners.');
+  requireRule(!g.strongholdCards || JSON.stringify(g.strongholdCards) === JSON.stringify(createStrongholdCards()),
+    'Start with unused Stronghold Cards before assigning ownership.');
+  requireFreshBaseRuntime(g);
   initializeSetup(g);
+  if (advancedPreview) g.advancedPreview = true;
 }
 function skillRule<T>(operation: () => T): T {
   try {
@@ -5935,19 +6004,7 @@ function initializeSetupGameForAudit(state: Game, homeworlds: boolean, nexus = f
   homeworldDefenseIntegrity(state);
   homeworldShipmentIntegrity(state);
   const g = structuredClone(state);
-  requireRule(
-    g.status === 'lobby' && !g.setupStage && g.turn === 1 && g.phase === 0,
-    'The audit initializer requires a fresh lobby.',
-  );
-  requireRule(
-    g.players.length >= 2 &&
-      g.players.length <= 6 &&
-      new Set(g.players.map((p) => p.id)).size === g.players.length &&
-      new Set(g.players.map((p) => p.faction)).size === g.players.length &&
-      g.players.some((p) => p.id === g.host) &&
-      g.players.every((p) => p.id && p.ready),
-    'The audit initializer requires two through six distinct ready players and an existing host.',
-  );
+  requireFreshSetup(g, homeworlds || nexus || ix || factions);
   requireRule(
     (homeworlds || nexus || ix || choam || factions || g.expansions.length === 0) &&
       (choam || factions || !g.expansions.includes('choam')) &&
@@ -5974,47 +6031,6 @@ function initializeSetupGameForAudit(state: Game, homeworlds: boolean, nexus = f
       ? '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.',
   );
-  requireRule(
-    !g.deck.length &&
-      !g.discard.length &&
-      !g.spiceDeck.length &&
-      !g.spiceDiscard.some((pile) => pile.length) &&
-      !g.traitorReserve?.length &&
-      g.ecazLoyalty === undefined &&
-      !g.decision &&
-      !g.response &&
-      !g.battle &&
-      !g.winner.length &&
-      g.players.every(
-        (p) =>
-          !p.hand.length &&
-          !p.traitors.length &&
-          !p.traitorChoices.length &&
-          Object.keys(p.forces).length === 0 &&
-          p.reserves === 20 &&
-          p.tanks === 0 &&
-          p.spice === 0 &&
-          p.moved === 0 &&
-          !p.shipped &&
-          !p.prediction &&
-          !p.advisorSetup &&
-          (!p.elites ||
-            ((homeworlds || nexus || ix || factions) &&
-              p.faction === 'ixians' &&
-              p.elites.reserves === 7 &&
-              p.elites.tanks === 0 &&
-              p.elites.revived === 0 &&
-              Object.keys(p.elites.forces).length === 0)),
-      ),
-    'The audit initializer cannot redeal or replace existing game pieces.',
-  );
-  requireRule(
-    Object.keys(g.playerPositions ?? {}).every((id) =>
-      g.players.some((p) => p.id === id),
-    ),
-    'Player circles must belong to seated players.',
-  );
-  normalizedPlayerPositions(g);
   initializeSetup(g);
   return normalizeAutomaticGame(g);
 }
@@ -20722,6 +20738,7 @@ function normalizeCardNames(g: Game) {
   ]);
 }
 export function applyAction(state: Game, id: string, action: Action): Game {
+  advancedPreviewIntegrity(state);
   harkonnenExchangeIntegrity(state);
   validateEcazLoyalty(state);
   ecazTreacheryIntegrity(state);
@@ -20990,6 +21007,7 @@ function settleAutomaticContinuations(g: Game) {
 }
 /** Internal authoritative continuation. Callers must persist with their usual CAS fence. */
 export function normalizeAutomaticGame(state: Game): Game {
+  advancedPreviewIntegrity(state);
   harkonnenExchangeIntegrity(state);
   validateEcazLoyalty(state);
   ecazTreacheryIntegrity(state);
@@ -22647,6 +22665,27 @@ function applyActionInner(
     return g;
   }
   if (g.status === 'lobby') {
+    if (t === 'rules') {
+      requireRule(id === g.host, 'Only the host can change the rules mode.');
+      requireRule(typeof action.advanced === 'boolean' &&
+        Object.keys(action).every(key => key === 'type' || key === 'advanced'),
+      'Choose Basic or Advanced preview rules.');
+      if (g.advanced === action.advanced) return g;
+      if (action.advanced) {
+        const blocked = baseStartProfileBlock(g);
+        requireRule(!blocked, blocked ?? 'This configuration cannot use Advanced preview.');
+      }
+      const removedStrongholds = !action.advanced && !!g.strongholdCards;
+      if (removedStrongholds) {
+        requireRule(JSON.stringify(g.strongholdCards) === JSON.stringify(createStrongholdCards()),
+          'Only unused lobby Stronghold Cards can be cleared when choosing Basic rules.');
+        g.strongholdCards = null;
+      }
+      g.advanced = action.advanced;
+      g.players.forEach(player => (player.ready = !!player.bot));
+      log(g, `${p.name} selected ${g.advanced ? 'Advanced preview' : 'Basic'} rules.${removedStrongholds ? ' Stronghold Cards were disabled because they require Advanced rules.' : ''} Human readiness was cleared; AI seats remain ready.`);
+      return g;
+    }
     if (t === 'configureBot') {
       const positions = normalizedPlayerPositions(g);
       const quote = quoteLobbyBotConfiguration(
@@ -22785,7 +22824,10 @@ function applyActionInner(
     }
     if (t === 'start') {
       requireRule(id === g.host, 'Only the host can start the game.');
-      start(g);
+      requireRule(Object.keys(action).every(key => key === 'type' || key === 'advancedPreview') &&
+        (action.advancedPreview === undefined || action.advancedPreview === true),
+      'Start this table, or explicitly choose Advanced preview.');
+      start(g, action.advancedPreview === true);
       return g;
     }
     if (t === 'faction') {
@@ -24629,6 +24671,7 @@ function applyActionInner(
   throw new RuleError('That action is not available.');
 }
 export function viewGame(state: Game, id: string) {
+  advancedPreviewIntegrity(state);
   harkonnenExchangeIntegrity(state);
   validateEcazLoyalty(state);
   ecazTreacheryIntegrity(state);
@@ -24739,6 +24782,7 @@ export function viewGame(state: Game, id: string) {
     mentat: projectedMentat(g, id),
     rihani: projectedRihani(g, id),
     advanced: g.advanced,
+    advancedPreview: g.advancedPreview === true,
     dukeVidal: g.dukeVidal
       ? { ...g.dukeVidal, leader: projectLeader(g, g.dukeVidal.leader, id) }
       : null,