v1.0.0: extract theme from cl-tty.box to own cl-tty.theme package

The theme system (theme class, define-preset, load-preset, theme-color)
was part of the bloated cl-tty.box package even though it had nothing
to do with boxes, spans, or component rendering. It only used cl-tty.backend
for the *theme-colors* hash table.

Changes:
- added defpackage :cl-tty.theme as the first block in theme.lisp
  (inline defpackage avoids ASDF dependency ordering issues with
   separate package files)
- removed theme exports from cl-tty.box defpackage
- theme tests now run in their own THEME-SUITE (16 tests) instead of
  part of BOX-SUITE
- box suite drops from 64 to 48 tests (16 moved to theme suite)
- updated ASDF, run-all-tests.lisp

All 15 test suites pass at 100%.

org/package.org

@@ -173,9 +173,6 @@ theme object is passed in from the application level. This separation
 means themes can be swapped without touching component instances.
 
 #+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/components/package.lisp
-   ;; Theme engine
-   #:theme #:make-theme #:theme-mode
-   #:theme-color #:load-preset #:define-preset
    ;; Container components (merged from cl-tty.container)
    #:scroll-box #:make-scroll-box
    #:scroll-box-scroll-y #:scroll-box-scroll-x

org/theme.org

@@ -43,6 +43,17 @@ and the backend's ~*theme-colors*~ for SGR resolution.
 - ~:default~ — gold/accent on dark blue-gray
 - ~:nord~ — cool blue nord palette
 
+* Package definition
+
+#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/components/theme.lisp
+(defpackage :cl-tty.theme
+  (:use :cl :cl-tty.backend)
+  (:export
+   #:theme #:make-theme #:theme-mode
+   #:theme-color #:load-preset #:define-preset))
+(in-package :cl-tty.theme)
+#+END_SRC
+
 * Tests
 
 ** Test header
@@ -50,8 +61,18 @@ and the backend's ~*theme-colors*~ for SGR resolution.
 Package declaration and test suite registration.
 
 #+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/components/theme-tests.lisp
-(in-package :cl-tty-box-test)
-(in-suite box-suite)
+(defpackage :cl-tty-theme-test
+  (:use :cl :cl-tty.theme :fiveam)
+  (:export #:run-tests))
+(in-package :cl-tty-theme-test)
+
+(def-suite theme-suite :description "Theme engine tests")
+(in-suite theme-suite)
+
+(defun run-tests ()
+  (let ((result (run 'theme-suite)))
+    (fiveam:explain! result)
+    (uiop:quit 0)))
 #+END_SRC
 
 ** Test: theme-create-default
@@ -201,7 +222,7 @@ hash table). Using ~make-hash-table~ as the ~:initform~ ensures each
 instance gets its own table instead of sharing one.
 
 #+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/components/theme.lisp
-(in-package :cl-tty.box)
+(in-package :cl-tty.theme)
 
 (defclass theme ()
   ((mode :initform :dark :initarg :mode :accessor theme-mode)