Implement mixed Planetologist advisor gather continuation

game/planetologist-movement.ts

@@ -1,8 +1,47 @@
 import { FACTIONS } from './catalog';
 import { nativeExpansionLeaderSkillsProfile } from './leader-skill-profile';
-import type { Game, GameView } from './engine';
+import type { Game, GameView, Player } from './engine';
 import { splitLocation } from './board';
+import { isAdvisor } from './advisors';
+import { presenceAt, type ForcePresence } from './force-presence';
 
+type MovementPlayer = Pick<Player, 'id' | 'faction' | 'advisors'> & ForcePresence & {
+  moved?: number;
+  advisorFlipMovementBlocked?: boolean | { turn: number; move: number };
+};
+type MovementGame = Pick<Game, 'advanced' | 'turn'> & {
+  players: readonly (Pick<Player, 'id'> & ForcePresence)[];
+};
+type AdvisorGatherEntry = Readonly<{ requiresFlip: boolean; blocked: string | null }>;
+const noAdvisorGather: AdvisorGatherEntry = { requiresFlip: false, blocked: null };
+const fighterAdvisorGather: AdvisorGatherEntry = { requiresFlip: true, blocked: null };
+const freshAdvisorGather: AdvisorGatherEntry = {
+  requiresFlip: true, blocked: 'Fresh spiritual advisors cannot become fighters during this turn.',
+};
+const canceledAdvisorGather: AdvisorGatherEntry = {
+  requiresFlip: true, blocked: 'Advisor flipping was canceled for this movement. Choose a legal replacement without flipping advisors.',
+};
+
+/** The canceled native flip stays unavailable for this movement opportunity. */
+export function advisorFlipMovementBlocked(game: Pick<Game, 'turn'>, player: MovementPlayer): boolean {
+  const blocked = player.advisorFlipMovementBlocked;
+  return typeof blocked === 'boolean' ? blocked :
+    blocked?.turn === game.turn && blocked.move === player.moved;
+}
+
+/** Provisional simultaneous gather: declare one common fighter arrival before
+ * either source moves; native cancellation keeps both original groups in place. */
+export function planetologistGatherAdvisorEntry(game: MovementGame, player: MovementPlayer,
+  origins: readonly string[], destination: string): AdvisorGatherEntry {
+  if (!game.advanced || player.faction !== 'beneGesserit' || origins.length !== 2 ||
+      isAdvisor(player, origins[0]) === isAdvisor(player, origins[1]) ||
+      presenceAt(player, destination) ||
+      !game.players.some(other => other.id !== player.id && presenceAt(other, destination)))
+    return noAdvisorGather;
+  if (origins.some(origin => player.advisors?.[origin]?.lockedTurn === game.turn))
+    return freshAdvisorGather;
+  return advisorFlipMovementBlocked(game, player) ? canceledAdvisorGather : fighterAdvisorGather;
+}
 export type PlanetologistMoveMode = 'range' | 'gather';
 export type PlanetologistMovement = {
   leader: string;