Show the neoirc-cli screen without waiting at start-up (closes #226)

Run added the start-up status bar and welcome lines through
SetStatus and AddStatus before it started the tview event loop. Both
wait for that loop, so neoirc-cli stopped before it showed its
screen. They now run on a goroutine, as typed lines do.

Run now passes a new UI to run, which holds the start-up path and
returns its error. TestStartUp calls run with a simulation screen. It
fails unless, within five seconds, the status window holds two lines:
first the one with "Welcome to neoirc-cli", then the /connect hint.

Model: opus-5-5

internal/cli/app_internal_test.go

@@ -4,6 +4,8 @@ import (
 	"io"
 	"net/http"
 	"net/http/httptest"
+	"slices"
+	"strings"
 	"testing"
 	"time"
 
@@ -359,7 +361,8 @@ func TestLinesKeepOrder(t *testing.T) {
 
 // TestStartUp runs the client's start-up path on a simulation
 // screen. It fails unless the event loop starts and the status
-// window gets the welcome lines.
+// window gets two lines: first the one that holds "Welcome to
+// neoirc-cli", then the /connect hint.
 func TestStartUp(t *testing.T) {
 	t.Parallel()
 
@@ -386,16 +389,22 @@ func TestStartUp(t *testing.T) {
 	})
 
 	// run adds the welcome lines on a goroutine, so the status
-	// window is read until they are there. Each read waits for
+	// window is read until it holds two lines. Each read waits for
 	// the event loop, so the reads run on a goroutine too, which
-	// this test stops waiting for after eventLoopTimeout.
+	// this test stops waiting for after eventLoopTimeout. The
-	shown := make(chan struct{})
+	// channel has one slot, so that goroutine can still end.
+	shown := make(chan []string, 1)
 
 	go func() {
 		for {
-			lines, _ := bufferState(ui, "(status)")
+			var lines []string
-			if lines == welcomeLines {
+
-				close(shown)
+			ui.app.QueueUpdate(func() {
+				lines = slices.Clone(ui.getOrCreateBuffer("(status)").Lines)
+			})
+
+			if len(lines) == welcomeLines {
+				shown <- lines
 
 				return
 			}
@@ -404,12 +413,22 @@ func TestStartUp(t *testing.T) {
 		}
 	}()
 
+	var lines []string
+
 	select {
-	case <-shown:
+	case lines = <-shown:
 	case <-time.After(eventLoopTimeout):
 		t.Fatalf("the status window did not get the welcome lines within %v",
 			eventLoopTimeout)
 	}
+
+	if !strings.Contains(lines[0], "Welcome to neoirc-cli") {
+		t.Errorf("first status line is %q, want the welcome line", lines[0])
+	}
+
+	if !strings.Contains(lines[1], "/connect <server-url>") {
+		t.Errorf("second status line is %q, want the /connect hint", lines[1])
+	}
 }
 
 // TestOwnEventFromOtherClient checks that a message, notice,