Show the connection state in the neoirc-cli status bar (closes #229)

The status bar has colour tags turned on, so tview read "[connected]"
and "[disconnected]" as colour names and dropped them. It dropped the
bracketed part of a nick such as "erin[away]" the same way.

renderStatusBar now passes the whole status line through tview.Escape,
so every bracket shows as it is. TestStartUp checks that the status
bar shows [disconnected] at start-up. TestStatusBar checks [connected]
with plain nicks and with nicks that hold brackets.

Model: opus-5-5

internal/cli/ui.go

@@ -332,10 +332,13 @@ func (ui *UI) renderStatusBar(
 
 	ui.statusBar.Clear()
 
-	_, _ = fmt.Fprintf(ui.statusBar,
+	// The status bar has colour tags turned on, so tview would read
+	// "[connected]", or a name in square brackets, as a colour tag
+	// and drop it. Escape makes it show every bracket as it is.
+	_, _ = fmt.Fprint(ui.statusBar, tview.Escape(fmt.Sprintf(
 		" [%s] %s %s %s%s",
 		connStatus, nick, bufInfo, target, unread,
-	)
+	)))
 }
 
 func (ui *UI) getOrCreateBuffer(name string) *Buffer {