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.lisp

@@ -9,8 +9,7 @@
 
 (defgeneric component-children (component)
   (:documentation "Return the children of COMPONENT, or nil.")
-  (:method ((bx box)) nil)
-  (:method ((tx text)) nil))
+  (:method ((c t)) nil))
 
 (defgeneric component-parent (component)
   (:documentation "Return the parent of COMPONENT, or nil.")