fix: set input-blocking nil on input window so agent responses render

Croatoan child windows don't inherit the screen's :input-blocking nil.
Without explicit (setf (input-blocking iw) nil), get-char blocks the
main loop indefinitely, preventing redraw from running. New agent
messages queued by the reader-loop thread were never rendered until
the user pressed a key.

Now the loop runs at 30fps and responses appear immediately.

lisp/gateway-tui-main.lisp

@@ -239,6 +239,7 @@
                               (parse-integer (uiop:getenv "TUI_SWANK_PORT")))
                             4006)))
        (setf (function-keys-enabled-p iw) t
+             (input-blocking iw) nil
              (st :dirty) (list t t t))
        (connect-daemon)
        (when (> swank-port 0)

org/gateway-tui-main.org

@@ -276,6 +276,7 @@ Event handlers + daemon I/O + main loop.
                               (parse-integer (uiop:getenv "TUI_SWANK_PORT")))
                             4006)))
        (setf (function-keys-enabled-p iw) t
+             (input-blocking iw) nil
              (st :dirty) (list t t t))
        (connect-daemon)
        (when (> swank-port 0)