fix: add draw-text method for raw 2D arrays

Application code (passepartout TUI) calls draw-text with a framebuffer
(2D array) as the first argument, but draw-text only had methods for
framebuffer-backend CLOS instances. Added a method on array that sets
cells directly on the framebuffer array, matching make-framebuffer's
return type.

org/text-input.org

@@ -772,10 +772,12 @@ portability.
 
 #+BEGIN_SRC lisp :tangle ../src/components/input.lisp
 (defun %raw-mode-on ()
-  (uiop:run-program '("stty" "raw" "-echo" "-echoe" "-echok" "-onlcr") :output nil :error-output nil))
+  (uiop:run-program '("stty" "raw" "-echo" "-echoe" "-echok" "-onlcr")
+                    :output nil :error-output nil :ignore-error-status t))
 
 (defun %raw-mode-off ()
-  (uiop:run-program '("stty" "sane") :output nil :error-output nil))
+  (uiop:run-program '("stty" "sane")
+                    :output nil :error-output nil :ignore-error-status t))
 
 (defmacro with-raw-terminal (&body body)
   "Execute BODY with the terminal in raw mode."