feat: 添加用户记账连击（streak）功能，包括服务、处理器、模型和仓库层。

internal/service/streak_service.go

@@ -241,3 +241,11 @@ func (s *StreakService) CheckAndResetStreak(userID uint) error {
 
 	return nil
 }
+
+// GetContributionData returns daily transaction counts for the past year
+func (s *StreakService) GetContributionData(userID uint) ([]models.DailyContribution, error) {
+	now := time.Now()
+	startDate := now.AddDate(-1, 0, 0) // 1 year ago
+
+	return s.repo.GetDailyContribution(userID, startDate, now)
+}