i3: Move kitty daemonization into own script

.config/kitty/daemon.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+# SPDX-License-Identifier: MIT
+# Copyright (c) 2025 Julian Prein
+#
+# Daemonize kitty by launching one hidden instance that new invocations can use
+# to create new OS windows. This makes kitty startup a lot faster since all
+# windows can now share a single CPU process and GPU sprite cache. Additionally
+# allow remote_control over a socket, so that kitty-cwd works.
+#
+# To launch new invocations using the daemon created by this script use:
+#
+#     kitty --single-instance
+#
+# NOTE: `--start-as hidden` needs kitty 0.42.0 or later.
+
+kitty \
+	--single-instance \
+	--start-as hidden \
+	--detach \
+	-o allow_remote_control=socket-only \
+	--listen-on unix:/tmp/mykitty