feat: add safe growth report persistence and AvalAI client

internal/growthreport/time.go

@@ -0,0 +1,11 @@
+package growthreport
+
+import "time"
+
+func NextTehranRefresh(now time.Time) time.Time {
+	location, err := time.LoadLocation("Asia/Tehran")
+	if err != nil { location = time.FixedZone("Asia/Tehran", 3*60*60+30*60) }
+	local := now.In(location)
+	return time.Date(local.Year(), local.Month(), local.Day()+1, 0, 0, 0, 0, location).UTC()
+}
+