Update algorithm and API documentation for smoking tracking app

- Enhanced the algorithm documentation to clarify the calculation of smoking intervals, including default values and edge cases.
- Updated API documentation to reflect changes in response formats, including the addition of `exceeded_yesterday` and adjustments to time formatting to RFC3339.
- Improved descriptions of user profile management and AI suggestions in the product documentation, ensuring consistency across all related files.
- Removed outdated sequence diagram and UI documentation files to streamline project resources.

internal/smoke/service/smoke_log_service.go

@@ -123,6 +123,7 @@ type SmokeHomeSummary struct {
 	TodayCount           int
 	ResistedCount        int
 	ReducedFromYesterday int
+	ExceededYesterday    bool
 }
 
 // DashboardWeeklyStat 表示某一天的抽烟支数以及是否为今天。
@@ -290,9 +291,7 @@ func (s *SmokeLogService) HomeSummary(ctx context.Context, uid int, asOf time.Ti
 	}
 
 	reduced := int(yesterdayCount - todayCount)
-	if reduced < 0 {
-		reduced = 0
-	}
+	exceeded := reduced < 0
 
 	var lastSmokeAt *time.Time
 	var last smokemodel.SmokeLog
@@ -315,6 +314,7 @@ func (s *SmokeLogService) HomeSummary(ctx context.Context, uid int, asOf time.Ti
 		TodayCount:           int(todayCount),
 		ResistedCount:        int(resistedCount),
 		ReducedFromYesterday: reduced,
+		ExceededYesterday:    exceeded,
 	}, nil
 }