feat(tui): column sort with indicator on monitors table

Press < / > to cycle sort column (Status, Name, Latency). Press r to
reverse direction. Sorted column shows ▲/▼ arrow in the header.

Groups always float to top. Sort applies to ungrouped monitors and
group children independently. Default: Status descending (DOWN first).

internal/tui/data.go

@@ -49,7 +49,7 @@ func writeCmd(op string, fn func() error) tea.Cmd {
 	}
 }
 
-func sortSitesForDisplay(allSites []models.Site, collapsed map[int]bool) []models.Site {
+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)
 	for _, s := range allSites {
@@ -68,8 +68,26 @@ func sortSitesForDisplay(allSites []models.Site, collapsed map[int]bool) []model
 		sort.SliceStable(c, func(i, j int) bool { return siteOrder(c[i]) < siteOrder(c[j]) })
 		children[pid] = c
 	}
-	sort.Slice(ungrouped, func(i, j int) bool { return ungrouped[i].ID < ungrouped[j].ID })
-	sort.SliceStable(ungrouped, func(i, j int) bool { return siteOrder(ungrouped[i]) < siteOrder(ungrouped[j]) })
+
+	sortSlice := func(s []models.Site) {
+		sort.Slice(s, func(i, j int) bool { return s[i].ID < s[j].ID })
+		sort.SliceStable(s, func(i, j int) bool {
+			var less bool
+			switch sortCol {
+			case sortName:
+				less = strings.ToLower(s[i].Name) < strings.ToLower(s[j].Name)
+			case sortLatency:
+				less = s[i].Latency < s[j].Latency
+			default:
+				less = siteOrder(s[i]) < siteOrder(s[j])
+			}
+			if !sortAsc {
+				return less
+			}
+			return !less
+		})
+	}
+	sortSlice(ungrouped)
 
 	var ordered []models.Site
 	for _, g := range groups {
@@ -99,7 +117,7 @@ func filterSites(sites []models.Site, needle string) []models.Site {
 // separately via loadTabDataCmd.
 func (m *Model) refreshLive() {
 	allSites := m.engine.GetAllSites()
-	ordered := sortSitesForDisplay(allSites, m.collapsed)
+	ordered := sortSitesForDisplay(allSites, m.collapsed, m.sortColumn, m.sortAsc)
 	if m.filterText != "" {
 		ordered = filterSites(ordered, m.filterText)
 	}

internal/tui/data_test.go

@@ -12,7 +12,7 @@ func TestSortSitesForDisplay_GroupsFirst(t *testing.T) {
 		{SiteConfig: models.SiteConfig{ID: 1, Name: "group-a", Type: "group"}, SiteState: models.SiteState{Status: "UP"}},
 		{SiteConfig: models.SiteConfig{ID: 2, Name: "child", Type: "http", ParentID: 1}, SiteState: models.SiteState{Status: "UP"}},
 	}
-	result := sortSitesForDisplay(sites, nil)
+	result := sortSitesForDisplay(sites, nil, sortStatus, false)
 	if len(result) != 3 {
 		t.Fatalf("expected 3 sites, got %d", len(result))
 	}
@@ -34,7 +34,7 @@ func TestSortSitesForDisplay_CollapsedHidesChildren(t *testing.T) {
 		{SiteConfig: models.SiteConfig{ID: 3, Name: "child-2", Type: "http", ParentID: 1}, SiteState: models.SiteState{Status: "UP"}},
 	}
 	collapsed := map[int]bool{1: true}
-	result := sortSitesForDisplay(sites, collapsed)
+	result := sortSitesForDisplay(sites, collapsed, sortStatus, false)
 	if len(result) != 1 {
 		t.Fatalf("collapsed group should hide children, got %d items", len(result))
 	}
@@ -49,7 +49,7 @@ func TestSortSitesForDisplay_StatusOrdering(t *testing.T) {
 		{SiteConfig: models.SiteConfig{ID: 2, Name: "down-site", Type: "http"}, SiteState: models.SiteState{Status: "DOWN"}},
 		{SiteConfig: models.SiteConfig{ID: 3, Name: "late-site", Type: "http"}, SiteState: models.SiteState{Status: "LATE"}},
 	}
-	result := sortSitesForDisplay(sites, nil)
+	result := sortSitesForDisplay(sites, nil, sortStatus, false)
 	if result[0].Status != "DOWN" {
 		t.Errorf("DOWN should sort first, got %s", result[0].Status)
 	}

internal/tui/tab_sites.go

@@ -106,6 +106,24 @@ func (m Model) computeLayout() tableLayout {
 		}
 	}
 
+	sortColMap := map[int]colKey{
+		sortStatus:  colStatus,
+		sortName:    colName,
+		sortLatency: colLatency,
+	}
+	if sortedKey, ok := sortColMap[m.sortColumn]; ok {
+		arrow := "▼"
+		if m.sortAsc {
+			arrow = "▲"
+		}
+		for i, k := range active {
+			if k == sortedKey {
+				headers[i] = headers[i] + arrow
+				break
+			}
+		}
+	}
+
 	numCols := len(headers)
 	borderOverhead := 2 + (numCols - 1)
 	avail := cw - chromePadH - 2 - borderOverhead - fixed

internal/tui/tui.go

@@ -102,6 +102,13 @@ const (
 	panelDetail   = 2
 )
 
+const (
+	sortStatus  = 0
+	sortName    = 1
+	sortLatency = 2
+	sortMax     = 3
+)
+
 type sessionState int
 
 const (
@@ -125,6 +132,8 @@ type Model struct {
 	settingsSection int
 	cursor          int
 	selectedID      int
+	sortColumn      int
+	sortAsc         bool
 	tableOffset     int
 	maxTableRows    int
 	termWidth       int

internal/tui/update.go

@@ -532,6 +532,23 @@ func (m *Model) handleDashboardKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 			m.recalcLayout()
 			return m, nil
 		}
+	case ">", ".":
+		if m.currentTab == tabMonitors {
+			m.sortColumn = (m.sortColumn + 1) % sortMax
+			m.sortAsc = false
+			m.refreshLive()
+		}
+	case "<", ",":
+		if m.currentTab == tabMonitors {
+			m.sortColumn = (m.sortColumn - 1 + sortMax) % sortMax
+			m.sortAsc = false
+			m.refreshLive()
+		}
+	case "r":
+		if m.currentTab == tabMonitors {
+			m.sortAsc = !m.sortAsc
+			m.refreshLive()
+		}
 	case "tab":
 		m.switchTab(m.currentTab + 1)
 	case "left":

internal/tui/view_dashboard.go

@@ -308,7 +308,7 @@ func (m Model) renderFooter(stats dashboardStats) string {
 		} else if m.detailOpen {
 			keys = "[i]Close [Enter]Expand [h]History [s]SLA [e]Edit [l]Logs [↑/↓]Select [T]Theme [q]Quit"
 		} else {
-			keys = "[/]Filter [i]Info [Enter]Detail [n]New [e]Edit [d]Del [l]Logs [T]Theme [Tab]Switch [q]Quit"
+			keys = "[/]Filter [i]Info [Enter]Detail [</>]Sort [r]Reverse [n]New [e]Edit [d]Del [l]Logs [T]Theme [Tab]Switch [q]Quit"
 		}
 	case tabMaint:
 		keys = "[n]New [x]End [d]Del [T]Theme [Tab]Switch [q]Quit"