Implement Homeworld mechanics through Caladan reinforcement checkpoint

Connect typed Homeworld custody, transport, battle, income, revival and Caladan reinforcement flows with private multiplayer recovery and controls. Preserve the optimized test workflow and keep unfinished rules modes gated. Verified with 3682 offline tests, typecheck, lint, production build and 40 HTTP tests; existing saved games remain unchanged.

game/ambassador-phase.ts

@@ -0,0 +1,78 @@
+import type { Game } from './engine';
+import { location } from './board';
+import { validAmbassadorResume } from './ambassador-resume';
+import { validateHomeworldRevivalReturn } from './homeworld-revival-return';
+import { validateHomeworldVictoryReturn } from './homeworld-victory-return';
+import {
+  validateHomeworldArrival,
+  type HomeworldArrivalFrame,
+  type HomeworldArrivalTag,
+} from './homeworld-arrival';
+
+export type AmbassadorPhaseContext = Pick<
+  Game,
+  | 'turn'
+  | 'phase'
+  | 'players'
+  | 'homeworlds'
+  | 'homeworldRevivalReturn'
+  | 'homeworldRevivalProgress'
+  | 'homeworldVictoryReinforcement'
+  | 'lastBattleContext'
+  | 'pendingAmbassador'
+>;
+
+/** Extra phases belong only to the recorded arrival and its actual BG suffixes. */
+export function ambassadorPhaseAllowed(g: AmbassadorPhaseContext): boolean {
+  const entry = g.pendingAmbassador;
+  const candidates: {
+    tag: HomeworldArrivalTag;
+    frame: HomeworldArrivalFrame | undefined;
+  }[] = [
+    { tag: 'revivalEvent', frame: g.homeworldRevivalReturn },
+    { tag: 'victoryEvent', frame: g.homeworldVictoryReinforcement },
+  ];
+  const matching = candidates.filter(
+    ({ tag, frame }) =>
+      entry &&
+      (entry[tag] !== undefined ||
+        (Array.isArray(frame?.ambassadors) &&
+          frame.ambassadors.some((record) => record?.event === entry.event))),
+  );
+  if (!matching.length) return g.phase === 1 || g.phase === 5;
+  if (matching.length !== 1) return false;
+  const { tag, frame } = matching[0];
+  if (
+    !entry ||
+    !frame ||
+    entry[tag] !== frame.event ||
+    frame.stage !== 'arrival' ||
+    frame.turn !== g.turn ||
+    frame.phase !== g.phase ||
+    entry.turn !== g.turn ||
+    entry.phase !== g.phase ||
+    entry.resume !== 'none' ||
+    !validAmbassadorResume(g, entry)
+  )
+    return false;
+  try {
+    if (tag === 'revivalEvent')
+      validateHomeworldRevivalReturn(g, g.homeworldRevivalReturn);
+    else validateHomeworldVictoryReturn(g);
+    validateHomeworldArrival(g, frame, tag);
+  } catch {
+    return false;
+  }
+  const record = frame.ambassadors!.at(-1);
+  if (
+    !record ||
+    record.completed ||
+    record.event !== entry.event ||
+    record.entrant !== entry.entrant ||
+    record.destination !== location(entry.territory, entry.sector)
+  )
+    return false;
+  return record.parent === undefined
+    ? entry.guildAdvisorOrigin === undefined
+    : entry.guildAdvisorOrigin?.event === record.parent;
+}