refactor: introduce Wire dependency injection and interface-based architecture

- Add Google Wire for compile-time dependency injection
- Replace concrete service types with interfaces across handlers
- Remove global state (DB, cache) in favor of constructor injection
- Split monolithic files into focused modules:
  - config: separate files for each config domain
  - dto: converters split by domain (user, post, message, group)
  - cache: separate metrics.go and redis_cache.go
- Introduce unified apperrors package with string-based error codes
- Add transaction support with context-aware repository methods
- Upgrade golang.org/x/crypto from 0.17.0 to 0.26.0

internal/wire/service.go

@@ -0,0 +1,189 @@
+package wire
+
+import (
+	"carrot_bbs/internal/cache"
+	"carrot_bbs/internal/config"
+	"carrot_bbs/internal/pkg/email"
+	"carrot_bbs/internal/pkg/gorse"
+	"carrot_bbs/internal/pkg/openai"
+	"carrot_bbs/internal/pkg/s3"
+	"carrot_bbs/internal/pkg/sse"
+	"carrot_bbs/internal/repository"
+	"carrot_bbs/internal/service"
+
+	"github.com/google/wire"
+	"gorm.io/gorm"
+)
+
+// ServiceSet Service 层 Provider Set
+var ServiceSet = wire.NewSet(
+	// JWT 服务（需要配置参数）
+	ProvideJWTService,
+
+	// 基础服务
+	ProvideEmailService,
+	ProvidePostAIService,
+
+	// 核心服务（按依赖顺序）
+	ProvidePushService,
+	ProvideSystemMessageService,
+	ProvidePostService,
+	ProvideCommentService,
+	ProvideMessageService,
+	ProvideNotificationService,
+	ProvideUserService,
+	ProvideStickerService,
+	ProvideVoteService,
+	ProvideChatService,
+	ProvideScheduleService,
+	ProvideGroupService,
+	ProvideUploadService,
+)
+
+// ProvideJWTService 提供 JWT 服务
+func ProvideJWTService(cfg *config.Config) *service.JWTService {
+	return service.NewJWTService(
+		cfg.JWT.Secret,
+		int64(cfg.JWT.AccessTokenExpire.Seconds()),
+		int64(cfg.JWT.RefreshTokenExpire.Seconds()),
+	)
+}
+
+// ProvideEmailService 提供邮件服务
+func ProvideEmailService(client email.Client) service.EmailService {
+	return service.NewEmailService(client)
+}
+
+// ProvidePostAIService 提供 AI 服务
+func ProvidePostAIService(client openai.Client) *service.PostAIService {
+	return service.NewPostAIService(client)
+}
+
+// ProvidePushService 提供推送服务
+func ProvidePushService(
+	pushRepo *repository.PushRecordRepository,
+	deviceTokenRepo *repository.DeviceTokenRepository,
+	messageRepo *repository.MessageRepository,
+	sseHub *sse.Hub,
+) service.PushService {
+	return service.NewPushService(pushRepo, deviceTokenRepo, messageRepo, sseHub)
+}
+
+// ProvideSystemMessageService 提供系统消息服务
+func ProvideSystemMessageService(
+	notifyRepo *repository.SystemNotificationRepository,
+	pushService service.PushService,
+	userRepo *repository.UserRepository,
+	postRepo *repository.PostRepository,
+	cacheBackend cache.Cache,
+) service.SystemMessageService {
+	return service.NewSystemMessageService(notifyRepo, pushService, userRepo, postRepo, cacheBackend)
+}
+
+// ProvidePostService 提供帖子服务
+func ProvidePostService(
+	postRepo *repository.PostRepository,
+	systemMessageService service.SystemMessageService,
+	gorseClient gorse.Client,
+	postAIService *service.PostAIService,
+	cacheBackend cache.Cache,
+	txManager repository.TransactionManager,
+) service.PostService {
+	return service.NewPostService(postRepo, systemMessageService, gorseClient, postAIService, cacheBackend, txManager)
+}
+
+// ProvideCommentService 提供评论服务
+func ProvideCommentService(
+	commentRepo *repository.CommentRepository,
+	postRepo *repository.PostRepository,
+	systemMessageService service.SystemMessageService,
+	gorseClient gorse.Client,
+	postAIService *service.PostAIService,
+	cacheBackend cache.Cache,
+) *service.CommentService {
+	return service.NewCommentService(commentRepo, postRepo, systemMessageService, gorseClient, postAIService, cacheBackend)
+}
+
+// ProvideMessageService 提供消息服务
+func ProvideMessageService(
+	db *gorm.DB,
+	messageRepo *repository.MessageRepository,
+	cacheBackend cache.Cache,
+) *service.MessageService {
+	return service.NewMessageService(db, messageRepo, cacheBackend)
+}
+
+// ProvideNotificationService 提供通知服务
+func ProvideNotificationService(
+	notificationRepo *repository.NotificationRepository,
+	cacheBackend cache.Cache,
+) *service.NotificationService {
+	return service.NewNotificationService(notificationRepo, cacheBackend)
+}
+
+// ProvideUserService 提供用户服务
+func ProvideUserService(
+	userRepo *repository.UserRepository,
+	systemMessageService service.SystemMessageService,
+	emailService service.EmailService,
+	cacheBackend cache.Cache,
+) service.UserService {
+	return service.NewUserService(userRepo, systemMessageService, emailService, cacheBackend)
+}
+
+// ProvideStickerService 提供表情服务
+func ProvideStickerService(
+	stickerRepo repository.StickerRepository,
+) service.StickerService {
+	return service.NewStickerService(stickerRepo)
+}
+
+// ProvideVoteService 提供投票服务
+func ProvideVoteService(
+	voteRepo *repository.VoteRepository,
+	postRepo *repository.PostRepository,
+	cache cache.Cache,
+	postAIService *service.PostAIService,
+	systemMessageService service.SystemMessageService,
+) *service.VoteService {
+	return service.NewVoteService(voteRepo, postRepo, cache, postAIService, systemMessageService)
+}
+
+// ProvideChatService 提供聊天服务
+// Note: sensitiveService 传 nil，与 main.go 保持一致
+func ProvideChatService(
+	db *gorm.DB,
+	messageRepo *repository.MessageRepository,
+	userRepo *repository.UserRepository,
+	sseHub *sse.Hub,
+	cacheBackend cache.Cache,
+) service.ChatService {
+	return service.NewChatService(db, messageRepo, userRepo, nil, sseHub, cacheBackend)
+}
+
+// ProvideScheduleService 提供日程服务
+func ProvideScheduleService(
+	scheduleRepo repository.ScheduleRepository,
+) service.ScheduleService {
+	return service.NewScheduleService(scheduleRepo)
+}
+
+// ProvideGroupService 提供群组服务
+func ProvideGroupService(
+	db *gorm.DB,
+	groupRepo repository.GroupRepository,
+	userRepo *repository.UserRepository,
+	messageRepo *repository.MessageRepository,
+	sseHub *sse.Hub,
+	cacheBackend cache.Cache,
+) service.GroupService {
+	return service.NewGroupService(db, groupRepo, userRepo, messageRepo, sseHub, cacheBackend)
+}
+
+// ProvideUploadService 提供上传服务
+func ProvideUploadService(
+	s3Client *s3.Client,
+	userService service.UserService,
+) *service.UploadService {
+	return service.NewUploadService(s3Client, userService)
+}