✨Feature: implement return to town and resume dungeon flow with state management

src/types/state.ts

@@ -209,7 +209,9 @@ export type RunState = {
   id: string;
   campaignId: string;
   status: "active" | "paused" | "completed" | "failed";
+  phase: "dungeon" | "town";
   startedAt: string;
+  lastTownAt?: string;
   currentLevel: number;
   currentRoomId?: string;
   dungeon: DungeonState;