refactor: replace dynamic imports with event bus pattern

Replace 12 dynamic `await import()` calls with domain events emitted
through the existing systemEvents bus, breaking circular dependencies
between services (economy/inventory/leveling -> quest, * -> dashboard).

- Add `emitAsync` to SystemEventEmitter for sequential listener awaiting,
  preserving DB transaction atomicity for quest progress tracking
- Add DOMAIN event constants (BALANCE_CHANGED, XP_GAINED, ITEM_COLLECTED,
  ITEM_USED, TRANSFER_COMPLETED, DAILY_CLAIMED, TRIVIA_*, EXAM_PASSED)
- Create shared/lib/eventWiring.ts to register all domain event listeners
- Convert quest event calls to `await systemEvents.emitAsync()` (5 calls)
- Convert dashboard event calls to `systemEvents.emit()` fire-and-forget (5 calls)
- Convert exam.service.ts userService import to static import (1 call)
- Convert dashboard.service.ts events import to static import (1 call)
- Leave inventory.service.ts validateAndExecuteEffect import unchanged (Task 3)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

bot/index.ts

@@ -2,12 +2,16 @@ import { AuroraClient } from "@/lib/BotClient";
 import { env } from "@shared/lib/env";
 import { join } from "node:path";
 import { initializeConfig } from "@shared/lib/config";
+import { registerDomainEventListeners } from "@shared/lib/eventWiring";
 
 import { startWebServerFromRoot } from "../api/src/server";
 
 // Initialize config from database
 await initializeConfig();
 
+// Register domain event listeners before loading commands/events
+registerDomainEventListeners();
+
 // Load commands & events
 await AuroraClient.loadCommands();
 await AuroraClient.loadEvents();