fix: backend-size (TIOCGWINSZ), kitty keyboard enable, Wayland clipboard, SIGWINCH handler

backend/modern.lisp

@@ -140,18 +140,20 @@ as a fallback when a keyword is not in *named-colors*.")
   (make-instance 'modern-backend :output-stream (or output-stream *standard-output*)))
 
 (defmethod initialize-backend ((b modern-backend))
-  ;; Enter raw mode, enable mouse, bracketed paste
+  ;; Enter raw mode, enable mouse, bracketed paste, kitty keyboard
   (backend-write b (format nil "~C[?1049h" #\Esc))  ; alt screen
   (backend-write b (format nil "~C[?1000h" #\Esc))  ; mouse basic
   (backend-write b (format nil "~C[?1002h" #\Esc))  ; mouse drag
   (backend-write b (format nil "~C[?1006h" #\Esc))  ; SGR mouse
   (backend-write b (format nil "~C[?2004h" #\Esc))  ; bracketed paste
+  (backend-write b (format nil "~C[?u" #\Esc))      ; kitty keyboard
   (cursor-hide b)
   (finish-output (backend-output-stream b))
   b)
 
 (defmethod shutdown-backend ((b modern-backend))
   (cursor-show b)
+  (backend-write b (format nil "~C[?u" #\Esc))      ; restore default keyboard
   (backend-write b (format nil "~C[?2004l" #\Esc))  ; disable bracketed paste
   (backend-write b (format nil "~C[?1006l" #\Esc))  ; disable SGR mouse
   (backend-write b (format nil "~C[?1002l" #\Esc))
@@ -161,8 +163,17 @@ as a fallback when a keyword is not in *named-colors*.")
   (values))
 
 (defmethod backend-size ((b modern-backend))
-  ;; Default fallback — real implementation queries terminal
-  (values 80 24))
+  ;; Query actual terminal dimensions via TIOCGWINSZ ioctl
+  (let* ((+tiocgwinsz+ 21523)  ; 0x5413 on Linux
+         (winsize (sb-alien:make-alien sb-alien:unsigned-short 4)))
+    (unwind-protect
+         (progn
+           (sb-unix:unix-ioctl (sb-sys:fd-stream-fd (backend-output-stream b))
+                               +tiocgwinsz+
+                               winsize)
+           (values (sb-alien:deref winsize 1)  ;; cols
+                   (sb-alien:deref winsize 0))) ;; rows
+      (sb-alien:free-alien winsize))))
 
 (defmethod backend-write ((b modern-backend) string)
   (let ((stream (backend-output-stream b)))