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>

shared/modules/economy/economy.service.ts

@@ -1,6 +1,7 @@
 import { users, transactions, userTimers } from "@db/schema";
 import { eq, sql, and } from "drizzle-orm";
 import { config } from "@shared/lib/config";
+import { systemEvents, EVENTS } from "@shared/lib/events";
 import { withTransaction } from "@/lib/db";
 import type { Transaction } from "@shared/lib/types";
 import { UserError } from "@shared/lib/errors";
@@ -62,12 +63,7 @@ export const economyService = {
             });
 
             // Record dashboard event
-            const { dashboardService } = await import("@shared/modules/dashboard/dashboard.service");
-            await dashboardService.recordEvent({
-                type: 'info',
-                message: `${sender.username} transferred ${amount.toLocaleString()} AU to User ID ${toUserId}`,
-                icon: '💸'
-            });
+            systemEvents.emit(EVENTS.DOMAIN.TRANSFER_COMPLETED, { username: sender.username, amount, toUserId });
 
             return { success: true, amount };
         }, tx);
@@ -158,12 +154,7 @@ export const economyService = {
             });
 
             // Record dashboard event
-            const { dashboardService } = await import("@shared/modules/dashboard/dashboard.service");
-            await dashboardService.recordEvent({
-                type: 'success',
-                message: `${user.username} claimed daily reward: ${totalReward.toLocaleString()} AU`,
-                icon: '☀️'
-            });
+            systemEvents.emit(EVENTS.DOMAIN.DAILY_CLAIMED, { username: user.username, amount: totalReward });
 
             return { claimed: true, amount: totalReward, streak, nextReadyAt, isWeekly: isWeeklyCurrent, weeklyBonus: weeklyBonusAmount };
         }, tx);
@@ -197,8 +188,7 @@ export const economyService = {
             });
 
             // Trigger Quest Event
-            const { questService } = await import("@shared/modules/quest/quest.service");
-            await questService.handleEvent(id, type, 1, txFn);
+            await systemEvents.emitAsync(EVENTS.DOMAIN.BALANCE_CHANGED, { userId: id, type, tx: txFn });
 
             return user;
         }, tx);