v0.3.3: SIGWINCH, scroll clamp, /quit, /reconnect, history, message vector

SIGWINCH: handle KEY_RESIZE (410) in main loop — re-measure screen,
re-create status/chat/input windows at new dimensions, force redraw.

Scroll clamp: PageUp clamped to (max 0 (- total 1)), prevents scrolling
past message list end. Status bar shows 'msgs:N scroll:0'.

/quit: saves :input-history to ~/.cache/passepartout/history (one line
per entry, most recent first), sends goodbye handshake, sets :running nil.

/reconnect: closes stale socket via disconnect-daemon, re-runs
connect-daemon with retry backoff. Connection-loss detection: reader-loop
counts consecutive nils; after 10, queues :disconnected event. Handler
clears :connected/:busy, shows red system message.

Load-history: reads ~/.cache/passepartout/history on startup, populates
:input-history for up-arrow recall.

Message vector: :messages init as adjustable vector with fill pointer.
add-msg uses vector-push-extend (O(1) append). view-chat uses aref
(O(1) access) instead of nth (O(n) for lists).

lisp/gateway-tui-model.lisp

@@ -28,7 +28,8 @@
   (setf *state*
         (list :running t :mode :chat :connected nil :stream nil
               :input-buffer nil :input-history nil :input-hpos 0
-              :messages nil :scroll-offset 0 :busy nil :cursor-pos 0
+              :messages (make-array 16 :adjustable t :fill-pointer 0)
+              :scroll-offset 0 :busy nil :cursor-pos 0
               :dirty (list nil nil nil))))
 
 (defun now ()
@@ -59,7 +60,7 @@
         (setf (st :cursor-pos) (1- pos))))))
 
 (defun add-msg (role content)
-  (push (list :role role :content content :time (now)) (st :messages))
+  (vector-push-extend (list :role role :content content :time (now)) (st :messages))
   (setf (st :dirty) (list t t nil)))
 
 (defun queue-event (ev)