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/layout-engine.org

@@ -337,11 +337,11 @@ means a full Yoga FFI binding is unnecessary — ~200 lines of CL math.
    (justify-content :initform :flex-start :initarg :justify-content
                     :accessor layout-node-justify-content)
    ;; Box model
-   (padding  :initform '(:top 0 :right 0 :bottom 0 :left 0)
+  (padding  :initform (list :top 0 :right 0 :bottom 0 :left 0)
              :initarg :padding :accessor layout-node-padding)
-   (margin   :initform '(:top 0 :right 0 :bottom 0 :left 0)
+  (margin   :initform (list :top 0 :right 0 :bottom 0 :left 0)
              :initarg :margin :accessor layout-node-margin)
-   (border   :initform '(:top 0 :right 0 :bottom 0 :left 0)
+  (border   :initform (list :top 0 :right 0 :bottom 0 :left 0)
              :initarg :border :accessor layout-node-border)
    (gap      :initform 0 :initarg :gap :accessor layout-node-gap)
    ;; Position
@@ -383,10 +383,12 @@ means a full Yoga FFI binding is unnecessary — ~200 lines of CL math.
 
 (defun normalize-box (spec)
   "Convert a box property spec to ( :top N :right N :bottom N :left N )."
-  (cond ((null spec)        '(:top 0 :right 0 :bottom 0 :left 0))
-        ((numberp spec)     `(:top ,spec :right ,spec :bottom ,spec :left ,spec))
-        ((getf spec :top)   spec)
-        (t                  `(:top 0 :right 0 :bottom 0 :left 0))))
+  (cond ((null spec) (list :top 0 :right 0 :bottom 0 :left 0))
+        ((numberp spec) (list :top spec :right spec :bottom spec :left spec))
+        (t (loop with result = (list :top 0 :right 0 :bottom 0 :left 0)
+                 for (key val) on spec by #'cddr
+                 do (setf (getf result key) val)
+                 finally (return result)))))
 #+END_SRC
 
 *** Tree Manipulation