feat(tui): mouse click for settings sections, column sort, logs panel

- Click Alerts/Nodes/Users sub-tabs in settings to switch sections
- Click STATUS/NAME/LATENCY column headers to sort (click again
  to reverse direction)
- Logs panel show/hide: [l] toggles sidebar visibility, click
  focused panel to hide. Monitors expand to full width when hidden.
- Logs full-screen: Enter when focused on logs opens scrollable
  full-screen log view with severity tags, filter toggle [f],
  and live updates

internal/tui/update.go

@@ -924,13 +924,7 @@ func (m *Model) handleClick(msg tea.MouseMsg) (tea.Model, tea.Cmd) {
 		if m.zones.Get("panel-monitors").InBounds(msg) {
 			m.focusedPanel = panelMonitors
 		} else if m.zones.Get("panel-logs").InBounds(msg) {
-			if m.focusedPanel == panelLogs {
-				m.logsOpen = false
-				m.focusedPanel = panelMonitors
-				m.recalcLayout()
-			} else {
 			m.focusedPanel = panelLogs
-			}
 			return m, nil
 		} else if m.detailOpen && m.zones.Get("panel-detail").InBounds(msg) {
 			m.focusedPanel = panelDetail