Quit with Ctrl+C only; q is an ordinary key everywhere

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019reK4DUGYqDUjniWYJvwUW

internal/ui/app_test.go

@@ -38,3 +38,11 @@ func TestOnlyFunctionKeysSwitchViews(t *testing.T) {
 		}
 	}
 }
+
+func TestQDoesNotQuit(t *testing.T) {
+	a := newTestApp(t)
+	ev := tcell.NewEventKey(tcell.KeyRune, 'q', 0)
+	if got := a.handleKey(ev); got != ev {
+		t.Error("q must be passed on as an ordinary key, not taken as quit")
+	}
+}