v0.12.0: Terminal capability detection, GPL 3.0 license, roadmap rewrite

LICENSE:
- Added GNU General Public License v3.0
- Updated README.org to reflect GPL 3.0

ROADMAP:
- Complete rewrite to reflect actual project state
- Removed croatoan/ncurses/Yoga FFI references
- Marked all 11 existing versions DONE
- Added v0.12.0-0.14.0 for new features (detection, pipeline, mouse)

DETECTION (v0.12.0):
- detect-backend: auto-detect modern vs simple backend
- detect-backend-by-env: check COLORTERM env var
- detect-backend-by-tty: check interactive-stream-p
- detect-backend-by-da1: query terminal via ESC[c (best-effort)
- *detected-backend* cache for zero-cost subsequent calls
- Added detection.lisp to ASDF and package exports
- Added 2 new tests (360 total, all passing)
- demo.lisp updated to use detect-backend

ORG BACKPORT (pre-existing fixes synced):
- dialog.org: render-dialog/render-toast fixes, class initforms
- scrollbox-tabbar.org: background-element -> bright-black, remove duplicate render
- select.org: remove duplicate render export
- text-input.org: remove duplicate %split-string, undo overflow fix
- layout-engine.org: quoted-literal -> list constructors, normalize-box rewrite
- mouse.org: add missing exports, fix test

org/scrollbox-tabbar.org

@@ -598,12 +598,12 @@ they are truncated with an ellipsis.
     (when (> content-h viewport-h)
       (let* ((thumb (scrollbar-thumb sy viewport-h content-h))
              (thumb-pos (round (* thumb viewport-h))))
-        (draw-rect backend (1- viewport-w) 0 1 viewport-h :bg :background-element)
+        (draw-rect backend (1- viewport-w) 0 1 viewport-h :bg :bright-black)
         (draw-text backend (1- viewport-w) thumb-pos "█" nil nil)))
     (when (> content-w viewport-w)
       (let* ((thumb (scrollbar-thumb sx viewport-w content-w))
              (thumb-pos (round (* thumb viewport-w))))
-        (draw-rect backend 0 (1- viewport-h) viewport-w 1 :bg :background-element)
+        (draw-rect backend 0 (1- viewport-h) viewport-w 1 :bg :bright-black)
         (draw-text backend thumb-pos (1- viewport-h) "█" nil nil)))))
 
 (defun update-sticky-scroll (sb)
@@ -681,6 +681,5 @@ they are truncated with an ellipsis.
    #:tab-bar #:make-tab-bar
    #:tab-bar-active #:tab-bar-tabs
    #:tab-bar-add #:tab-bar-next #:tab-bar-prev
-   #:tab-bar-select #:tab-bar-handle-key
-   #:render))
+   #:tab-bar-select #:tab-bar-handle-key))
 #+END_SRC