fix(capability): auth-service CapabilityGuard 类型修复 string → Capability

isCapabilityEnabled 参数需要 Capability 枚举类型，添加 as Capability 类型断言

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/services/auth-service/src/shared/guards/capability.guard.ts

@@ -8,6 +8,7 @@ import {
 import { Reflector } from '@nestjs/core';
 import { CAPABILITY_KEY } from '../decorators/require-capability.decorator';
 import { CapabilityService } from '@/application/services/capability.service';
+import { Capability } from '@/domain/value-objects/capability.vo';
 
 const CAPABILITY_LABELS: Record<string, string> = {
   LOGIN: '登录',
@@ -56,7 +57,7 @@ export class CapabilityGuard implements CanActivate {
     try {
       const isEnabled = await this.capabilityService.isCapabilityEnabled(
         accountSequence,
-        requiredCapability,
+        requiredCapability as Capability,
       );
 
       if (!isEnabled) {