fix: handle existing nvim config dir

install.sh

@@ -1,3 +1,20 @@
 #!/bin/sh
 # Installs the Neovim config only; Neovim itself must already be installed.
-mkdir -p "${XDG_CONFIG_HOME:-$HOME/.config}" && git clone https://git.sailorpunisher.com/sailor/nvim-config.git "${XDG_CONFIG_HOME:-$HOME/.config}/nvim"
+set -eu
+
+repo_url='https://git.sailorpunisher.com/sailor/nvim-config.git'
+target="${XDG_CONFIG_HOME:-$HOME/.config}/nvim"
+
+mkdir -p "${XDG_CONFIG_HOME:-$HOME/.config}"
+
+if [ -d "$target/.git" ]; then
+	git -C "$target" pull --ff-only
+	exit 0
+fi
+
+if [ -e "$target" ]; then
+	backup="${target}.bak-$(date +%Y%m%d-%H%M%S)"
+	mv "$target" "$backup"
+fi
+
+git clone "$repo_url" "$target"