review fixes: in-suite, version bump, default children method

Fixes from subagent review:
- render-tests.lisp: added (in-suite box-suite) — tests were registered
  to default suite, never executed by runner
- dirty-tests.lisp: same fix
- cl-tui.asd: version 0.2.0 → 0.3.0
- render.lisp: component-children default method (c t) nil for
  protocol completeness (component-parent already had this)

src/components/render-tests.lisp

@@ -1,4 +1,5 @@
 (in-package :cl-tui-box-test)
+(in-suite box-suite)
 
 (defun make-capturing-backend ()
   (let* ((s (make-string-output-stream))