Add monitoring service and database schema

- Implement monitoring service with heartbeat, lease tasks, resume tasks, and task result handling.
- Create monitoring time utilities for business date calculations.
- Add unit tests for date window resolution and business day handling.
- Define database schema for monitoring-related tables including quotas, daily reports, and task management.
- Establish migration scripts for creating and dropping monitoring tables.

server/internal/tenant/app/monitoring_time.go

@@ -0,0 +1,39 @@
+package app
+
+import (
+	"sync"
+	"time"
+)
+
+const monitoringBusinessTimeZoneName = "Asia/Shanghai"
+
+var (
+	monitoringBusinessLocationOnce  sync.Once
+	monitoringBusinessLocationValue *time.Location
+)
+
+func monitoringBusinessLocation() *time.Location {
+	monitoringBusinessLocationOnce.Do(func() {
+		loc, err := time.LoadLocation(monitoringBusinessTimeZoneName)
+		if err != nil {
+			monitoringBusinessLocationValue = time.FixedZone("UTC+8", 8*60*60)
+			return
+		}
+		monitoringBusinessLocationValue = loc
+	})
+
+	return monitoringBusinessLocationValue
+}
+
+func monitoringCanonicalBusinessDay(day time.Time) time.Time {
+	return monitoringBusinessDayAt(day, monitoringBusinessLocation())
+}
+
+func monitoringBusinessDayAndDateAt(now time.Time) (time.Time, string) {
+	businessDay := monitoringCanonicalBusinessDay(now)
+	return businessDay, businessDay.Format("2006-01-02")
+}
+
+func monitoringBusinessDateText(businessDay time.Time) string {
+	return monitoringCanonicalBusinessDay(businessDay).Format("2006-01-02")
+}