v1.0.0: merge container (scrollbox + tabbar) into cl-tty.box

Eliminates the cl-tty.container package by merging scrollbox and tabbar
components directly into cl-tty.box, where the component system lives.

Changes:
- added scrollbox/tabbar exports to cl-tty.box defpackage in package.org
- changed scrollbox.org in-package from cl-tty.container to cl-tty.box
- changed tabbar.org in-package from cl-tty.container to cl-tty.box
- tabbar's key-event-key references are qualified with cl-tty.input:
  (avoids circular :use dependency with cl-tty.input which :uses cl-tty.box)
- deleted container-package.org
- updated test packages, integration tests, scripts, ASDF
- all 14 test suites pass at 100%

org/scrollbox.org

@@ -46,7 +46,7 @@ the CLOS-based component protocol — ~render~ dispatches on the class,
 and dirty-mixin provides the marking machinery used by the refresh loop.
 
 #+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/components/scrollbox.lisp
-(in-package #:cl-tty.container)
+(in-package :cl-tty.box)
 
 (defclass scroll-box (dirty-mixin)
   ((children :initform nil :initarg :children
@@ -344,7 +344,7 @@ unconditionally; it runs the ~scrollbox-suite~ and prints results via
 
 #+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/tests/scrollbox-tabbar-tests.lisp
 (defpackage :cl-tty-scrollbox-test
-  (:use :cl :fiveam :cl-tty.backend :cl-tty.box :cl-tty.layout :cl-tty.input :cl-tty.container)
+  (:use :cl :fiveam :cl-tty.backend :cl-tty.box :cl-tty.layout :cl-tty.input)
   (:export #:run-tests))
 (in-package #:cl-tty-scrollbox-test)