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/trivia/trivia.service.ts

@@ -1,6 +1,7 @@
 import { users, userTimers, transactions } from "@db/schema";
 import { eq, and, sql } 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, SystemError } from "@shared/lib/errors";
@@ -232,12 +233,7 @@ class TriviaService {
                 });
 
             // Record dashboard event
-            const { dashboardService } = await import("@shared/modules/dashboard/dashboard.service");
-            await dashboardService.recordEvent({
-                type: 'info',
-                message: `${username} started a trivia game (${question.difficulty})`,
-                icon: '🎯'
-            });
+            systemEvents.emit(EVENTS.DOMAIN.TRIVIA_STARTED, { username, difficulty: question.difficulty });
 
             return session;
         });
@@ -293,12 +289,7 @@ class TriviaService {
                     where: eq(users.id, BigInt(userId))
                 });
 
-                const { dashboardService } = await import("@shared/modules/dashboard/dashboard.service");
-                await dashboardService.recordEvent({
-                    type: 'success',
-                    message: `${user?.username} won ${reward.toLocaleString()} AU from trivia!`,
-                    icon: '🎉'
-                });
+                systemEvents.emit(EVENTS.DOMAIN.TRIVIA_WON, { username: user?.username, reward });
             });
         }