chore(tui): visual polish — detail sections, column headers, alert detail

Detail panel:
- Grouped fields into sections (ENDPOINT, TIMING, HTTP, CONFIG)
- Omit Timeout when 0 (unconfigured)
- Omit Method when default GET
- Show explicit "200-299" when AcceptedCodes empty

Table:
- LATENCY header → LAT (design short, never truncate)

Alerts:
- Press [i] for alert detail panel: full config, health status,
  send counts, last error
- Keybinding display updated with [i]Info

Bundled remaining UX polish items from screenshot review.

internal/tui/tab_alerts.go

@@ -2,6 +2,7 @@ package tui
 
 import (
 	"fmt"
+	"strings"
 	"time"
 
 	"gitea.lerkolabs.com/lerko/uptop/internal/monitor"
@@ -173,6 +174,52 @@ func (m Model) viewAlertsTab() string {
 	)
 }
 
+func (m Model) viewAlertDetailPanel() string {
+	if m.cursor >= len(m.alerts) {
+		return ""
+	}
+	a := m.alerts[m.cursor]
+	h := m.engine.GetAlertHealth(a.ID)
+
+	var b strings.Builder
+
+	b.WriteString(subtleStyle.Render("  Alerts > ") + titleStyle.Render(a.Name) + "\n\n")
+
+	row := func(label, value string) {
+		fmt.Fprintf(&b, "  %-16s %s\n", subtleStyle.Render(label), value)
+	}
+
+	row("Type", fmtAlertType(a.Type))
+
+	if h.LastSendAt.IsZero() {
+		row("Health", subtleStyle.Render("never sent"))
+	} else if h.LastSendOK {
+		row("Health", specialStyle.Render("OK"))
+	} else {
+		row("Health", dangerStyle.Render("FAILED"))
+	}
+
+	if !h.LastSendAt.IsZero() {
+		row("Last Sent", h.LastSendAt.Format("2006-01-02 15:04:05")+" ("+fmtAlertLastSent(h)+")")
+	}
+	if h.SendCount > 0 {
+		row("Sends", fmt.Sprintf("%d sent, %d failed", h.SendCount, h.FailCount))
+	}
+	if h.LastError != "" {
+		row("Last Error", dangerStyle.Render(limitStr(h.LastError, 60)))
+	}
+
+	b.WriteString("\n" + subtleStyle.Render("  CONFIGURATION") + "\n")
+	for k, v := range a.Settings {
+		row(k, v)
+	}
+
+	b.WriteString("\n\n")
+	b.WriteString(subtleStyle.Render("  [i/Esc] Back  [e] Edit  [t] Test  [q] Quit"))
+
+	return lipgloss.NewStyle().Padding(1, 2).Render(b.String())
+}
+
 func (m *Model) initAlertHuhForm() tea.Cmd {
 	m.alertFormData = &alertFormData{
 		AlertType:         "discord",

internal/tui/tab_sites.go

@@ -378,7 +378,7 @@ func (m Model) viewSitesTab() string {
 
 	var groupRows map[int]bool
 	return m.renderTable(
-		[]string{"#", "NAME", "TYPE", "STATUS", "LATENCY", "UPTIME", "HISTORY", "SSL", "RETRY"},
+		[]string{"#", "NAME", "TYPE", "STATUS", "LAT", "UPTIME", "HISTORY", "SSL", "RETRY"},
 		len(m.sites),
 		func(start, end int) [][]string {
 			groupRows = make(map[int]bool)
@@ -764,6 +764,10 @@ func (m Model) viewDetailPanel() string {
 		fmt.Fprintf(&b, "  %-16s %s\n", subtleStyle.Render(label), value)
 	}
 
+	section := func(label string) {
+		b.WriteString("\n" + subtleStyle.Render("  "+label) + "\n")
+	}
+
 	row("Status", fmtStatus(site.Status, site.Paused, m.isMonitorInMaintenance(site.ID)))
 
 	if (site.Status == "DOWN" || site.Status == "SSL EXP" || site.Status == "LATE") && site.LastError != "" {
@@ -792,6 +796,8 @@ func (m Model) viewDetailPanel() string {
 			}
 		}
 	}
+
+	section("ENDPOINT")
 	row("Type", site.Type)
 	if site.URL != "" {
 		row("URL", site.URL)
@@ -802,31 +808,45 @@ func (m Model) viewDetailPanel() string {
 	if site.Port > 0 {
 		row("Port", strconv.Itoa(site.Port))
 	}
+
+	section("TIMING")
 	row("Interval", fmt.Sprintf("%ds", site.Interval))
-	row("Timeout", fmt.Sprintf("%ds", site.Timeout))
+	if site.Timeout > 0 {
+		row("Timeout", fmt.Sprintf("%ds", site.Timeout))
+	}
 	row("Latency", fmtLatency(site.Latency))
 	row("Uptime", fmtUptime(hist.Statuses))
+	if !site.LastCheck.IsZero() {
+		row("Last Check", site.LastCheck.Format("15:04:05"))
+	}
 
 	if site.Type == "http" {
-		row("Method", site.Method)
-		row("Codes", site.AcceptedCodes)
+		section("HTTP")
+		if site.Method != "" && site.Method != "GET" {
+			row("Method", site.Method)
+		}
+		codes := site.AcceptedCodes
+		if codes == "" {
+			codes = "200-299"
+		}
+		row("Codes", codes)
 		row("SSL", fmtSSL(site))
 		if site.IgnoreTLS {
 			row("TLS Verify", dangerStyle.Render("disabled"))
 		}
 	}
 
-	if site.MaxRetries > 0 {
-		row("Retries", fmtRetries(site))
-	}
-	if site.Regions != "" {
-		row("Regions", site.Regions)
-	}
-	if site.Description != "" {
-		row("Description", site.Description)
-	}
-	if !site.LastCheck.IsZero() {
-		row("Last Check", site.LastCheck.Format("15:04:05"))
+	if site.MaxRetries > 0 || site.Regions != "" || site.Description != "" {
+		section("CONFIG")
+		if site.MaxRetries > 0 {
+			row("Retries", fmtRetries(site))
+		}
+		if site.Regions != "" {
+			row("Regions", site.Regions)
+		}
+		if site.Description != "" {
+			row("Description", site.Description)
+		}
 	}
 
 	probeResults := m.engine.GetProbeResults(site.ID)

internal/tui/tui.go

@@ -68,6 +68,7 @@ const (
 	stateLogs
 	stateUsers
 	stateDetail
+	stateAlertDetail
 	stateFormSite
 	stateFormAlert
 	stateFormUser
@@ -384,6 +385,14 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 				return m, tea.Quit
 			}
 			return m, nil
+		case stateAlertDetail:
+			switch msg.String() {
+			case "i", "esc":
+				m.state = stateDashboard
+			case "q":
+				return m, tea.Quit
+			}
+			return m, nil
 		case stateDashboard, stateLogs, stateUsers:
 			switch msg.String() {
 			case "q":
@@ -497,6 +506,8 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			case "i":
 				if m.currentTab == 0 && len(m.sites) > 0 {
 					m.state = stateDetail
+				} else if m.currentTab == 1 && len(m.alerts) > 0 {
+					m.state = stateAlertDetail
 				}
 			case "x":
 				if m.currentTab == 4 && len(m.maintenanceWindows) > 0 {
@@ -818,6 +829,8 @@ func (m Model) View() string {
 		return ""
 	case stateDetail:
 		return m.viewDetailPanel()
+	case stateAlertDetail:
+		return m.viewAlertDetailPanel()
 	default:
 		return m.zones.Scan(m.viewDashboard())
 	}
@@ -954,7 +967,7 @@ func (m Model) viewDashboard() string {
 		case 0:
 			keys = "[/]Filter [n]New [e]Edit [i]Info [d]Del [p]Pause [T]Theme [Tab]Switch [q]Quit"
 		case 1:
-			keys = "[n]New [e]Edit [d]Del [t]Test [T]Theme [Tab]Switch [q]Quit"
+			keys = "[n]New [e]Edit [i]Info [d]Del [t]Test [T]Theme [Tab]Switch [q]Quit"
 		case 2:
 			keys = "[f]Filter [T]Theme [Tab]Switch [q]Quit"
 		case 4: