feat: Hijri calendar, virtual midnight crossover, overlap rejection, WAL mode

- Hijri (قمری) calendar added as 3rd calendar option with tabular conversion
- Calendar type select menu (like accent) with gregorian/jalali/hijri
- Calendar type applied to exports and reports
- Midnight crossover: virtual splits at computation time (no synthetic DB events)
  - Handles both UTC and local timezone boundaries
  - Timezone changes handled naturally (recomputed on-the-fly)
- Rate limiting per user ID instead of chat ID
- WAL mode enabled for SQLite
- Smart reply keyboard updates after every state change
- Overlapping time edits rejected (must preserve in/out alternation)
- Single event deletion warns if timeline needs repair
- Day off no longer prevents clock in/out
- Accent colors shown with descriptive names in select menu
- Delete button label changed to DEL for visual distinction

internal/bot/export.go

@@ -22,7 +22,7 @@ var themes = map[string]themeColors{
 	"catppuccin": {headerFill: "B48DED", border: "D9D0E8", totalFill: "F0E8FC"},
 }
 
-func GenerateMonthlyReport(store *db.Store, userID int64, timezone, accent string, year int, month time.Month) ([]byte, error) {
+func GenerateMonthlyReport(store *db.Store, userID int64, timezone, accent, calendar string, year int, month time.Month) ([]byte, error) {
 	theme, ok := themes[accent]
 	if !ok {
 		theme = themes["ocean"]
@@ -76,7 +76,15 @@ func GenerateMonthlyReport(store *db.Store, userID int64, timezone, accent strin
 		Alignment: &excelize.Alignment{Horizontal: "center", Vertical: "center"},
 	})
 
-	monthName := time.Date(year, month, 1, 0, 0, 0, 0, time.UTC).Format("January 2006")
+	var monthName string
+	switch calendar {
+	case "jalali":
+		monthName = fmt.Sprintf("%s %d", jalaliMonthNames[month-1], year)
+	case "hijri":
+		monthName = fmt.Sprintf("%s %d", hijriMonthNames[month-1], year)
+	default:
+		monthName = time.Date(year, month, 1, 0, 0, 0, 0, time.UTC).Format("January 2006")
+	}
 	f.SetCellValue(sheet, "A1", fmt.Sprintf("Work Time Report - %s", monthName))
 	f.MergeCell(sheet, "A1", "F1")
 	f.SetCellStyle(sheet, "A1", "F1", titleStyle)
@@ -120,15 +128,21 @@ func GenerateMonthlyReport(store *db.Store, userID int64, timezone, accent strin
 
 	for d := firstDay; !d.After(lastDay); d = d.AddDate(0, 0, 1) {
 		dateStr := d.Format("2006-01-02")
+		displayDate := dateStr
+		if calendar == "jalali" {
+			gy, gm, gd := parseGregorianDateKey(dateStr)
+			jy, jm, jd := gregorianToJalali(gy, gm, gd)
+			displayDate = fmt.Sprintf("%04d-%02d-%02d", jy, jm, jd)
+		} else if calendar == "hijri" {
+			gy, gm, gd := parseGregorianDateKey(dateStr)
+			hy, hm, hd := gregorianToHijri(gy, gm, gd)
+			displayDate = fmt.Sprintf("%04d-%02d-%02d", hy, hm, hd)
+		}
 
 		day, exists := dayMap[dateStr]
 		if !exists {
 			continue
 		}
-		if day.IsDayOff {
-			continue
-		}
-
 		events, err := store.EventsForDayByDayID(day.ID)
 		if err != nil {
 			return nil, err
@@ -137,12 +151,14 @@ func GenerateMonthlyReport(store *db.Store, userID int64, timezone, accent strin
 			continue
 		}
 
-		totals := ComputeDailyTotals(events, day.MinBreakThreshold)
+		dayStart := time.Date(d.Year(), d.Month(), d.Day(), 0, 0, 0, 0, loc).Unix()
+		dayEnd := time.Date(d.Year(), d.Month(), d.Day(), 23, 59, 59, 0, loc).Unix()
+		totals := ComputeDailyTotals(events, day.MinBreakThreshold, dayStart, dayEnd)
 		totalWork += totals.TotalSeconds
 		totalBreak += totals.BreakSeconds
 
 		cellDate, _ := excelize.CoordinatesToCellName(1, row)
-		f.SetCellValue(sheet, cellDate, dateStr)
+		f.SetCellValue(sheet, cellDate, displayDate)
 		f.SetCellStyle(sheet, cellDate, cellDate, dataStyle)
 
 		if len(events) > 0 {