feat(tui): add scrollbar gutter to titledPanelH

Opt-in scrollbar track on the right border edge when totalItems > bodyH.
Thin track (│) with muted thumb (┃) showing viewport position.

Monitors panel passes len(sites) to enable it. Detail and fullscreen
panels pass 0 to opt out. Any panel can opt in via the totalItems param.

internal/tui/data.go

@@ -50,6 +50,21 @@ func writeCmd(op string, fn func() error) tea.Cmd {
 	}
 }
 
+func (m *Model) saveBottomPanelPref() tea.Cmd {
+	v := "logs"
+	switch m.bottomPanel {
+	case bottomNone:
+		v = "none"
+	case bottomMaint:
+		v = "maint"
+	}
+	st := m.store
+	ctx := m.ctx
+	return writeCmd("Save bottom panel preference", func() error {
+		return st.SetPreference(ctx, "bottom_panel", v)
+	})
+}
+
 func sortSitesForDisplay(allSites []models.Site, collapsed map[int]bool, sortCol int, sortAsc bool) []models.Site {
 	var groups, ungrouped []models.Site
 	children := make(map[int][]models.Site)

internal/tui/panel.go

@@ -6,7 +6,7 @@ import (
 	"github.com/charmbracelet/lipgloss"
 )
 
-func (m Model) titledPanelH(title, content, footer string, width, height, scrollOffset int, focused bool) string {
+func (m Model) titledPanelH(title, content, footer string, width, height, scrollOffset, totalItems int, focused bool) string {
 	if height <= 0 {
 		return m.titledPanel(title, content, width, focused)
 	}
@@ -64,21 +64,48 @@ func (m Model) titledPanelH(title, content, footer string, width, height, scroll
 	}
 	visible := contentLines[scrollOffset:end]
 
-	borderLine := func(line string) string {
-		return bc.Render("│") + line + strings.Repeat(" ", max(0, innerW-lipgloss.Width(line))) + bc.Render("│")
+	showScrollbar := totalItems > 0 && totalItems > bodyH
+	var thumbStart, thumbEnd int
+	if showScrollbar {
+		thumbSize := bodyH * bodyH / totalItems
+		if thumbSize < 1 {
+			thumbSize = 1
+		}
+		scrollRange := totalItems - bodyH
+		if scrollRange < 1 {
+			scrollRange = 1
+		}
+		trackSpace := bodyH - thumbSize
+		thumbStart = scrollOffset * trackSpace / scrollRange
+		thumbEnd = thumbStart + thumbSize
+	}
+
+	scrollTrack := bc.Render("│")
+	scrollThumb := lipgloss.NewStyle().Foreground(m.theme.Muted).Render("┃")
+
+	borderLine := func(line string, idx int) string {
+		rightBorder := bc.Render("│")
+		if showScrollbar && idx >= thumbStart && idx < thumbEnd {
+			rightBorder = scrollThumb
+		} else if showScrollbar {
+			rightBorder = scrollTrack
+		}
+		return bc.Render("│") + line + strings.Repeat(" ", max(0, innerW-lipgloss.Width(line))) + rightBorder
+	}
+	emptyLine := func(idx int) string {
+		return borderLine(strings.Repeat(" ", innerW), idx)
 	}
-	emptyLine := borderLine(strings.Repeat(" ", innerW))
 
 	var lines []string
 	lines = append(lines, top)
-	for _, line := range visible {
-		lines = append(lines, borderLine(line))
+	for i, line := range visible {
+		lines = append(lines, borderLine(line, i))
 	}
-	for len(lines) < height-1-len(footerLines) {
-		lines = append(lines, emptyLine)
+	for i := len(visible); len(lines) < height-1-len(footerLines); i++ {
+		lines = append(lines, emptyLine(i))
 	}
 	for _, line := range footerLines {
-		lines = append(lines, borderLine(line))
+		lines = append(lines, borderLine(line, -1))
 	}
 	lines = append(lines, bottom)
 

internal/tui/tui.go

@@ -243,6 +243,16 @@ func InitialModel(ctx context.Context, isAdmin bool, s store.Store, eng *monitor
 
 	detailPref, _ := s.GetPreference(ctx, "detail_open")
 
+	bp := bottomLogs
+	if bpPref, _ := s.GetPreference(ctx, "bottom_panel"); bpPref != "" {
+		switch bpPref {
+		case "none":
+			bp = bottomNone
+		case "maint":
+			bp = bottomMaint
+		}
+	}
+
 	return Model{
 		ctx:          ctx,
 		state:        stateDashboard,
@@ -257,7 +267,7 @@ func InitialModel(ctx context.Context, isAdmin bool, s store.Store, eng *monitor
 		theme:        theme,
 		themeIndex:   themeIdx,
 		st:           newStyles(theme),
-		bottomPanel:  bottomLogs,
+		bottomPanel:  bp,
 		detailOpen:   detailPref == "true",
 		demoMode:     os.Getenv("UPTOP_DEMO") == "1",
 		version:      version,

internal/tui/update.go

@@ -662,6 +662,7 @@ func (m *Model) handleDashboardKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 			m.focusedPanel = panelMaint
 		}
 		m.recalcLayout()
+		return m, m.saveBottomPanelPref()
 	case "l":
 		if m.bottomPanel == bottomLogs {
 			m.bottomPanel = bottomNone
@@ -671,6 +672,7 @@ func (m *Model) handleDashboardKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 			m.focusedPanel = panelLogs
 		}
 		m.recalcLayout()
+		return m, m.saveBottomPanelPref()
 	case "up", "k":
 		if m.focusedPanel == panelDetail && m.detailOpen {
 			m.detailScrollOffset--

internal/tui/view_dashboard.go

@@ -163,7 +163,7 @@ func (m Model) viewMonitorsLayout() string {
 
 	monTargetH := m.maxTableRows + 5
 	monitors := m.viewSitesTab()
-	monPanel := m.zones.Mark("panel-monitors", m.titledPanelH("Monitors", monitors, "", monW, monTargetH, 0, m.focusedPanel == panelMonitors))
+	monPanel := m.zones.Mark("panel-monitors", m.titledPanelH("Monitors", monitors, "", monW, monTargetH, 0, len(m.sites), m.focusedPanel == panelMonitors))
 
 	var topParts []string
 	topParts = append(topParts, monPanel)
@@ -181,7 +181,7 @@ func (m Model) viewMonitorsLayout() string {
 		monHeight := lipgloss.Height(monPanel)
 		detail := m.viewDetailInline(detailW-2, monHeight)
 		footer := m.detailFooter(detailW - 2)
-		detailPanel := m.zones.Mark("panel-detail", m.titledPanelH(title, detail, footer, detailW, monHeight, m.detailScrollOffset, m.focusedPanel == panelDetail))
+		detailPanel := m.zones.Mark("panel-detail", m.titledPanelH(title, detail, footer, detailW, monHeight, m.detailScrollOffset, 0, m.focusedPanel == panelDetail))
 		topParts = append(topParts, detailPanel)
 	}
 

internal/tui/view_detail_inline.go

@@ -75,7 +75,7 @@ func (m Model) viewDetailFullscreen() string {
 	}
 
 	return lipgloss.NewStyle().Padding(1, 2).Render(
-		m.titledPanelH(title, content, footer, availW, panelH, m.detailScrollOffset, true))
+		m.titledPanelH(title, content, footer, availW, panelH, m.detailScrollOffset, 0, true))
 }
 
 func (m Model) buildDetailContent(site models.Site, hist monitor.SiteHistory, width int, fullscreen bool) string {