fix(tui): esc closes detail split when list is focused

Previously esc in split view with list focus fell through to capture
focus. Now closes the detail pane and stays in stream browse mode.

internal/tui/model.go

@@ -455,6 +455,9 @@ func (m model) updateBrowse(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 				m.focus = focusList
 				return m, nil
 			}
+			m.splitDetail = false
+			m.recalcSizes()
+			return m, nil
 		}
 
 		if m.focus == focusDetail {