feat(monitor): add STALE state for push monitors

New intermediate state between LATE and DOWN at the midpoint of
the grace period. Gives operators earlier warning that a push
monitor has gone quiet. Includes dedicated orange theme color
across all 5 themes and proper styling in dashboard, detail
panel, and history view.

internal/monitor/monitor.go

@@ -509,6 +509,7 @@ func (e *Engine) checkPush(site models.Site) {
 	}
 
 	overdue := site.LastCheck.Add(interval)
+	staleMark := overdue.Add(grace / 2)
 	graceEnd := overdue.Add(grace)
 	now := time.Now()
 
@@ -516,6 +517,10 @@ func (e *Engine) checkPush(site models.Site) {
 		if site.Status != "DOWN" {
 			e.handleStatusChange(site, "DOWN", 0, 0, "heartbeat missed")
 		}
+	} else if now.After(staleMark) {
+		if site.Status != "STALE" {
+			e.handleStatusChange(site, "STALE", 0, 0, "heartbeat stale")
+		}
 	} else if now.After(overdue) {
 		if site.Status != "LATE" {
 			e.handleStatusChange(site, "LATE", 0, 0, "heartbeat overdue")

internal/monitor/monitor_test.go

@@ -571,6 +571,26 @@ func TestCheckPush_OverdueBecomesLate(t *testing.T) {
 	}
 }
 
+func TestCheckPush_OverdueBecomesStale(t *testing.T) {
+	ms := newMockStore()
+	e := newTestEngine(ms)
+	// interval=300, grace=150 (300/2), staleMark=overdue+75
+	// at 380s: past staleMark(375) but before graceEnd(450)
+	site := models.Site{
+		ID: 1, Name: "push", Type: "push", Status: "UP",
+		Interval:  300,
+		LastCheck: time.Now().Add(-380 * time.Second),
+	}
+	injectSite(e, site)
+
+	e.checkPush(site)
+
+	s, _ := getSite(e, 1)
+	if s.Status != "STALE" {
+		t.Errorf("expected STALE when past midpoint of grace, got %s", s.Status)
+	}
+}
+
 func TestCheckPush_WithinDeadline(t *testing.T) {
 	ms := newMockStore()
 	e := newTestEngine(ms)

internal/tui/format.go

@@ -22,6 +22,8 @@ func siteOrder(s models.Site) int {
 	switch s.Status {
 	case "DOWN", "SSL EXP":
 		return 0
+	case "STALE":
+		return 1
 	case "LATE":
 		return 1
 	case "PENDING":
@@ -142,6 +144,8 @@ func fmtStatus(status string, paused bool, inMaint bool, errCategory ErrorCatego
 		return dangerStyle.Render(status)
 	case "LATE":
 		return warnStyle.Render(status)
+	case "STALE":
+		return staleStyle.Render(status)
 	case "PENDING":
 		return subtleStyle.Render(status)
 	default:

internal/tui/tab_sites.go

@@ -158,7 +158,7 @@ func (m Model) viewSitesTab() string {
 					name = limitStr(name, nameW-2)
 				}
 
-				if (site.Status == "DOWN" || site.Status == "SSL EXP" || site.Status == "LATE") && site.LastError != "" {
+				if (site.Status == "DOWN" || site.Status == "SSL EXP" || site.Status == "LATE" || site.Status == "STALE") && site.LastError != "" {
 					nameLen := len([]rune(name))
 					errSpace := nameW - nameLen - 3
 					if errSpace > 10 {

internal/tui/theme.go

@@ -22,6 +22,7 @@ type Theme struct {
 	// Semantic
 	Success lipgloss.Color
 	Warning lipgloss.Color
+	Stale   lipgloss.Color
 	Danger  lipgloss.Color
 	Info    lipgloss.Color
 	Accent  lipgloss.Color
@@ -54,6 +55,7 @@ var themeFlexokiDark = Theme{
 	Subtle:     "#6F6E69",
 	Success:    "#879A39",
 	Warning:    "#D0A215",
+	Stale:      "#DA702C",
 	Danger:     "#D14D41",
 	Info:       "#4385BE",
 	Accent:     "#3AA99F",
@@ -74,6 +76,7 @@ var themeTokyoNight = Theme{
 	Subtle:     "#565f89",
 	Success:    "#9ece6a",
 	Warning:    "#e0af68",
+	Stale:      "#ff9e64",
 	Danger:     "#f7768e",
 	Info:       "#7aa2f7",
 	Accent:     "#7dcfff",
@@ -94,6 +97,7 @@ var themeGruvbox = Theme{
 	Subtle:     "#7c6f64",
 	Success:    "#b8bb26",
 	Warning:    "#fabd2f",
+	Stale:      "#fe8019",
 	Danger:     "#fb4934",
 	Info:       "#83a598",
 	Accent:     "#8ec07c",
@@ -114,6 +118,7 @@ var themeCatppuccinMocha = Theme{
 	Subtle:     "#6c7086",
 	Success:    "#a6e3a1",
 	Warning:    "#f9e2af",
+	Stale:      "#fab387",
 	Danger:     "#f38ba8",
 	Info:       "#89b4fa",
 	Accent:     "#94e2d5",
@@ -134,6 +139,7 @@ var themeNord = Theme{
 	Subtle:     "#4c566a",
 	Success:    "#a3be8c",
 	Warning:    "#ebcb8b",
+	Stale:      "#d08770",
 	Danger:     "#bf616a",
 	Info:       "#81a1c1",
 	Accent:     "#88c0d0",

internal/tui/tui.go

@@ -20,6 +20,7 @@ var (
 	subtleStyle  lipgloss.Style
 	specialStyle lipgloss.Style
 	warnStyle    lipgloss.Style
+	staleStyle   lipgloss.Style
 	dangerStyle  lipgloss.Style
 	titleStyle   lipgloss.Style
 	activeTab    lipgloss.Style
@@ -30,6 +31,7 @@ func applyTheme(t Theme) {
 	subtleStyle = lipgloss.NewStyle().Foreground(t.Subtle)
 	specialStyle = lipgloss.NewStyle().Foreground(t.Success)
 	warnStyle = lipgloss.NewStyle().Foreground(t.Warning)
+	staleStyle = lipgloss.NewStyle().Foreground(t.Stale)
 	dangerStyle = lipgloss.NewStyle().Foreground(t.Danger)
 	titleStyle = lipgloss.NewStyle().Foreground(t.Accent).Bold(true)
 	activeTab = lipgloss.NewStyle().Border(lipgloss.NormalBorder(), false, false, true, false).BorderForeground(t.Accent).Foreground(t.Accent).Bold(true).Padding(0, 1)

internal/tui/view_detail.go

@@ -43,7 +43,7 @@ func (m Model) viewDetailPanel() string {
 	errCat := classifyError(site.LastError, site.Type, site.StatusCode)
 	row("Status", fmtStatus(site.Status, site.Paused, m.isMonitorInMaintenance(site.ID), errCat))
 
-	if (site.Status == "DOWN" || site.Status == "SSL EXP" || site.Status == "LATE") && site.LastError != "" {
+	if (site.Status == "DOWN" || site.Status == "SSL EXP" || site.Status == "LATE" || site.Status == "STALE") && site.LastError != "" {
 		errWidth := m.termWidth - chromePadH - 19
 		if errWidth < 30 {
 			errWidth = 30

internal/tui/view_history.go

@@ -119,9 +119,14 @@ func (m Model) buildHistoryContent() string {
 		ts := sc.ChangedAt.Format("2006-01-02 15:04")
 
 		arrow := subtleStyle.Render(sc.FromStatus) + " → "
-		if sc.ToStatus == "UP" {
+		switch sc.ToStatus {
+		case "UP":
 			arrow += specialStyle.Render(sc.ToStatus)
-		} else {
+		case "LATE":
+			arrow += warnStyle.Render(sc.ToStatus)
+		case "STALE":
+			arrow += staleStyle.Render(sc.ToStatus)
+		default:
 			arrow += dangerStyle.Render(sc.ToStatus)
 		}