feat: Stage 2 — alert dashboard with live table and stats

Adds a bubbles/table alert list showing Name, Status, Started (relative
time), and Ack By columns. Stats bar shows total/firing/resolved counts.
Filter cycles firing → resolved → all with [f]. Auto-refresh fires on
the configured interval via tea.Tick. Table scrolls with j/k.

internal/tui/update.go

@@ -9,27 +9,55 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	case tea.WindowSizeMsg:
 		m.width = msg.Width
 		m.height = msg.Height
+		m.rebuildTable()
 		return m, nil
 
 	case connectedMsg:
 		m.connected = true
 		m.err = nil
-		m.statusMsg = "Connected to " + m.serverURL
-		return m, tea.Batch(tickCmd(m.refreshInterval), clearStatusCmd())
+		return m, tea.Batch(
+			tickCmd(m.refreshInterval),
+			fetchAlertsCmd(m.client, m.filterStatus),
+			fetchStatsCmd(m.client),
+		)
 
 	case connectErrMsg:
 		m.connected = false
 		m.err = msg.err
 		return m, nil
 
+	case alertsFetchedMsg:
+		m.alerts = msg.alerts
+		m.loading = false
+		m.rebuildTable()
+		return m, nil
+
+	case statsFetchedMsg:
+		m.stats = &msg.stats
+		return m, nil
+
+	case fetchDataErrMsg:
+		m.statusMsg = "error: " + msg.err.Error()
+		return m, clearStatusCmd()
+
 	case tickMsg:
-		return m, tickCmd(m.refreshInterval)
+		return m, tea.Batch(
+			tickCmd(m.refreshInterval),
+			fetchAlertsCmd(m.client, m.filterStatus),
+			fetchStatsCmd(m.client),
+		)
 
 	case clearStatusMsg:
 		m.statusMsg = ""
 		return m, nil
 
 	case tea.KeyMsg:
+		if m.activeSection == sectionAlerts && m.connected {
+			var tableCmd tea.Cmd
+			m.alertTable, tableCmd = m.alertTable.Update(msg)
+			m2, ourCmd := m.handleKey(msg)
+			return m2, tea.Batch(tableCmd, ourCmd)
+		}
 		return m.handleKey(msg)
 	}
 
@@ -37,17 +65,39 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 }
 
 func (m Model) handleKey(msg tea.KeyMsg) (Model, tea.Cmd) {
-	switch {
-	case msg.String() == "q" || msg.String() == "ctrl+c":
+	switch msg.String() {
+	case "q", "ctrl+c":
 		return m, tea.Quit
 
-	case msg.String() == "tab":
+	case "tab":
 		m.activeSection = (m.activeSection + 1) % 3
 		return m, nil
 
-	case msg.String() == "r":
+	case "r":
+		if !m.connected {
+			return m, connectCmd(m.client)
+		}
 		m.statusMsg = "Refreshing…"
-		return m, tea.Batch(connectCmd(m.client), clearStatusCmd())
+		return m, tea.Batch(
+			fetchAlertsCmd(m.client, m.filterStatus),
+			fetchStatsCmd(m.client),
+			clearStatusCmd(),
+		)
+
+	case "f":
+		if m.activeSection != sectionAlerts || !m.connected {
+			return m, nil
+		}
+		switch m.filterStatus {
+		case "firing":
+			m.filterStatus = "resolved"
+		case "resolved":
+			m.filterStatus = ""
+		default:
+			m.filterStatus = "firing"
+		}
+		m.loading = true
+		return m, fetchAlertsCmd(m.client, m.filterStatus)
 	}
 
 	return m, nil