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).