feat: a status pane, like lazygit's: version, updates, accounts, files and links

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

internal/ui/app/update_test.go

@@ -47,8 +47,8 @@ func TestUpdate(t *testing.T) {
 	if f.asked != 1 {
 		t.Fatalf("asked %d times at startup", f.asked)
 	}
-	if !strings.Contains(d.screen(), "v0.1.1 ↑ v0.2.0 U") {
-		t.Errorf("no update in the footer:\n%s", d.screen())
+	if scr := d.screen(); !strings.Contains(scr, "[0] lazysecrets v0.1.1") || !strings.Contains(scr, "↑ v0.2.0 U") {
+		t.Errorf("no update in the status pane:\n%s", scr)
 	}
 
 	// U: the changelog, without the install notes; u installs.