feat(tui): zebra striping, detail breadcrumb, sparkline stats, collapse persistence

Add alternating row backgrounds for easier table scanning. Detail panel
now shows breadcrumb path (Sites > Group > Name) and min/avg/max latency
stats below the sparkline. Group collapse state persists across restarts
via new preferences table in both SQLite and Postgres.

internal/metrics/prometheus_test.go

@@ -62,6 +62,8 @@ func (m *mockStore) AddMaintenanceWindow(models.MaintenanceWindow) error { retur
 func (m *mockStore) EndMaintenanceWindow(int) error                      { return nil }
 func (m *mockStore) DeleteMaintenanceWindow(int) error                   { return nil }
 func (m *mockStore) IsMonitorInMaintenance(int) (bool, error)            { return false, nil }
+func (m *mockStore) GetPreference(string) (string, error)                { return "", nil }
+func (m *mockStore) SetPreference(string, string) error                  { return nil }
 
 func TestMetricsHandler(t *testing.T) {
 	ms := &mockStore{

internal/store/postgres.go

@@ -67,6 +67,10 @@ func (d *PostgresDialect) CreateTablesSQL() []string {
 			created_by TEXT DEFAULT '',
 			created_at TIMESTAMP DEFAULT NOW()
 		)`,
+		`CREATE TABLE IF NOT EXISTS preferences (
+			key TEXT PRIMARY KEY,
+			value TEXT NOT NULL
+		)`,
 	}
 }
 

internal/store/sqlite.go

@@ -67,6 +67,10 @@ func (d *SQLiteDialect) CreateTablesSQL() []string {
 			created_by TEXT DEFAULT '',
 			created_at DATETIME DEFAULT CURRENT_TIMESTAMP
 		)`,
+		`CREATE TABLE IF NOT EXISTS preferences (
+			key TEXT PRIMARY KEY,
+			value TEXT NOT NULL
+		)`,
 	}
 }
 

internal/store/sqlstore.go

@@ -441,6 +441,24 @@ func (s *SQLStore) IsMonitorInMaintenance(monitorID int) (bool, error) {
 	return count > 0, nil
 }
 
+func (s *SQLStore) GetPreference(key string) (string, error) {
+	var value string
+	err := s.db.QueryRow(s.q("SELECT value FROM preferences WHERE key = ?"), key).Scan(&value)
+	if err != nil {
+		return "", err
+	}
+	return value, nil
+}
+
+func (s *SQLStore) SetPreference(key, value string) error {
+	if s.dollar {
+		_, err := s.db.Exec(s.q("INSERT INTO preferences (key, value) VALUES (?, ?) ON CONFLICT (key) DO UPDATE SET value = ?"), key, value, value)
+		return err
+	}
+	_, err := s.db.Exec("INSERT OR REPLACE INTO preferences (key, value) VALUES (?, ?)", key, value)
+	return err
+}
+
 func (s *SQLStore) ExportData() (models.Backup, error) {
 	sites, err := s.GetSites()
 	if err != nil {

internal/store/store.go

@@ -57,6 +57,10 @@ type Store interface {
 	DeleteMaintenanceWindow(id int) error
 	IsMonitorInMaintenance(monitorID int) (bool, error)
 
+	// Preferences
+	GetPreference(key string) (string, error)
+	SetPreference(key, value string) error
+
 	// Backup & Restore
 	ExportData() (models.Backup, error)
 	ImportData(data models.Backup) error

internal/tui/tab_sites.go

@@ -706,8 +706,19 @@ func (m Model) viewDetailPanel() string {
 
 	var b strings.Builder
 
-	title := titleStyle.Render(fmt.Sprintf("  %s", site.Name))
-	b.WriteString(title + "\n\n")
+	var breadcrumb string
+	if site.ParentID > 0 {
+		for _, s := range m.sites {
+			if s.ID == site.ParentID {
+				breadcrumb = subtleStyle.Render("  Sites > "+s.Name+" > ") + titleStyle.Render(site.Name)
+				break
+			}
+		}
+	}
+	if breadcrumb == "" {
+		breadcrumb = subtleStyle.Render("  Sites > ") + titleStyle.Render(site.Name)
+	}
+	b.WriteString(breadcrumb + "\n\n")
 
 	row := func(label, value string) {
 		b.WriteString(fmt.Sprintf("  %-16s %s\n", subtleStyle.Render(label), value))
@@ -777,8 +788,37 @@ func (m Model) viewDetailPanel() string {
 	const sparkWidth = 40
 	if site.Type == "push" {
 		b.WriteString("  " + heartbeatSparkline(hist.Statuses, sparkWidth))
+		if len(hist.Statuses) > 0 {
+			up := 0
+			for _, s := range hist.Statuses {
+				if s {
+					up++
+				}
+			}
+			b.WriteString(fmt.Sprintf("\n  %s %d/%d checks up",
+				subtleStyle.Render("Heartbeats"),
+				up, len(hist.Statuses)))
+		}
 	} else {
 		b.WriteString("  " + latencySparkline(hist.Latencies, sparkWidth))
+		if len(hist.Latencies) > 0 {
+			minL, maxL := hist.Latencies[0], hist.Latencies[0]
+			var total time.Duration
+			for _, l := range hist.Latencies {
+				total += l
+				if l < minL {
+					minL = l
+				}
+				if l > maxL {
+					maxL = l
+				}
+			}
+			avg := total / time.Duration(len(hist.Latencies))
+			b.WriteString(fmt.Sprintf("\n  %s %dms  %s %dms  %s %dms",
+				subtleStyle.Render("Min"), minL.Milliseconds(),
+				subtleStyle.Render("Avg"), avg.Milliseconds(),
+				subtleStyle.Render("Max"), maxL.Milliseconds()))
+		}
 	}
 
 	b.WriteString("\n\n")

internal/tui/table_helpers.go

@@ -21,6 +21,10 @@ var (
 
 	tableBorderStyle = lipgloss.NewStyle().
 				Foreground(lipgloss.Color("#444"))
+
+	tableZebraStyle = lipgloss.NewStyle().
+			Padding(0, 1).
+			Background(lipgloss.Color("#1a1a2e"))
 )
 
 type StyleOverride func(row, col int) *lipgloss.Style
@@ -67,6 +71,9 @@ func (m Model) renderTable(headers []string, items int, buildRows func(start, en
 				}
 			}
 			base := tableCellStyle
+			if row%2 == 1 {
+				base = tableZebraStyle
+			}
 			if isSelected {
 				base = tableSelectedStyle
 			}

internal/tui/tui.go

@@ -1,6 +1,7 @@
 package tui
 
 import (
+	"encoding/json"
 	"fmt"
 	"go-upkeep/internal/models"
 	"go-upkeep/internal/monitor"
@@ -105,6 +106,7 @@ func InitialModel(isAdmin bool, s store.Store, eng *monitor.Engine) Model {
 	vpLogs.SetContent("Waiting for logs...")
 	z := zone.New()
 	spring := harmonica.NewSpring(harmonica.FPS(10), 6.0, 0.4)
+	collapsed := loadCollapsed(s)
 	return Model{
 		state:        stateDashboard,
 		logViewport:  vpLogs,
@@ -114,10 +116,37 @@ func InitialModel(isAdmin bool, s store.Store, eng *monitor.Engine) Model {
 		engine:       eng,
 		zones:        z,
 		pulseSpring:  spring,
-		collapsed:    make(map[int]bool),
+		collapsed:    collapsed,
 	}
 }
 
+func loadCollapsed(s store.Store) map[int]bool {
+	m := make(map[int]bool)
+	raw, err := s.GetPreference("collapsed_groups")
+	if err != nil || raw == "" {
+		return m
+	}
+	var ids []int
+	if err := json.Unmarshal([]byte(raw), &ids); err != nil {
+		return m
+	}
+	for _, id := range ids {
+		m[id] = true
+	}
+	return m
+}
+
+func saveCollapsed(s store.Store, collapsed map[int]bool) {
+	var ids []int
+	for id, v := range collapsed {
+		if v {
+			ids = append(ids, id)
+		}
+	}
+	data, _ := json.Marshal(ids)
+	_ = s.SetPreference("collapsed_groups", string(data))
+}
+
 func (m Model) Init() tea.Cmd {
 	return tea.Batch(tea.ClearScreen, tea.Tick(time.Second, func(t time.Time) tea.Msg { return t }))
 }
@@ -401,6 +430,7 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 				if m.currentTab == 0 && len(m.sites) > 0 && m.sites[m.cursor].Type == "group" {
 					gid := m.sites[m.cursor].ID
 					m.collapsed[gid] = !m.collapsed[gid]
+					saveCollapsed(m.store, m.collapsed)
 					m.refreshData()
 				}
 			case "p":