fix(tui): maint tab — bump MONITORS/STARTED/ENDS min widths, respect column width

MONITORS min 13→15 (monitor names can be long, truncate to column width).
STARTED/ENDS min 10→14 (fits '18:30 May 28' = 12 chars + padding).
fmtMaintMonitorW truncates name to actual column width.

internal/tui/tab_maint.go

@@ -42,12 +42,16 @@ func fmtMaintType(t string) string {
 }
 
 func fmtMaintMonitor(monitorID int, sites []models.Site) string {
+	return fmtMaintMonitorW(monitorID, sites, 18)
+}
+
+func fmtMaintMonitorW(monitorID int, sites []models.Site, maxW int) string {
 	if monitorID == 0 {
 		return "All"
 	}
 	for _, s := range sites {
 		if s.ID == monitorID {
-			return limitStr(s.Name, 18)
+			return limitStr(s.Name, maxW)
 		}
 	}
 	return fmt.Sprintf("#%d", monitorID)
@@ -97,13 +101,14 @@ func (m Model) viewMaintTab() string {
 		{"#", "#", 4, 4, false},
 		{"TITLE", "TITLE", 12, 28, true},
 		{"TYPE", "TYPE", 13, 14, false},
-		{"MON", "MONITORS", 13, 20, false},
+		{"MON", "MONITORS", 15, 22, false},
 		{"STATUS", "STATUS", 11, 12, false},
-		{"START", "STARTED", 10, 16, false},
-		{"ENDS", "ENDS", 10, 16, false},
+		{"START", "STARTED", 14, 16, false},
+		{"ENDS", "ENDS", 14, 16, false},
 	}
 	headers, widths := m.computeTableLayout(cols, 0)
 	titleW := widths[1]
+	monW := widths[3]
 
 	return m.renderTable(
 		headers,
@@ -117,7 +122,7 @@ func (m Model) viewMaintTab() string {
 					strconv.Itoa(i + 1),
 					m.zones.Mark(fmt.Sprintf("maint-%d", i), limitStr(mw.Title, titleW-2)),
 					fmtMaintType(mw.Type),
-					fmtMaintMonitor(mw.MonitorID, allSites),
+					fmtMaintMonitorW(mw.MonitorID, allSites, monW-2),
 					fmtMaintStatus(mw),
 					fmtMaintTime(mw.StartTime),
 					fmtMaintTime(mw.EndTime),