refactor: replace standard log with zap logger and optimize code patterns

- Migrate all log.Printf/log.Println calls to structured zap logging
- Use cmp.Or for cleaner default value handling
- Replace manual loops with slices.ContainsFunc/IndexFunc
- Add batch query methods (IsLikedBatch, IsFavoritedBatch) to solve N+1 problem
- Update JSON tags from omitempty to omitzero for numeric fields
- Use errgroup-style wg.Go for worker goroutines
- Remove duplicate casbin/v2 dependency (keeping v3)
- Add plans/ to gitignore

cmd/server/wire_gen.go

@@ -109,7 +109,7 @@ func InitializeApp() (*App, error) {
 	adminDashboardHandler := handler.NewAdminDashboardHandler(adminDashboardService)
 	adminLogHandler := handler.NewAdminLogHandler(operationLogService, loginLogService, dataChangeLogService)
 	router := ProvideRouter(userHandler, postHandler, commentHandler, messageHandler, notificationHandler, uploadHandler, jwtService, pushHandler, systemMessageHandler, groupHandler, stickerHandler, gorseHandler, voteHandler, scheduleHandler, roleHandler, adminUserHandler, adminPostHandler, adminCommentHandler, adminGroupHandler, adminDashboardHandler, adminLogHandler, logService, userActivityService, casbinService)
-	app := NewApp(config, db, router, pushService, server)
+	app := NewApp(config, db, router, pushService, server, logger)
 	return app, nil
 }