feat: add package-lock.json for claude-code

Introduced a new `package-lock.json` for the `claude-code` project. This ensures consistent dependency management and locks all required versions for reproducible builds.

overlays/unstable/claude-code/update.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p nodePackages.npm nix-update
+
+set -euo pipefail
+
+version=$(npm view @anthropic-ai/claude-code version)
+
+# Generate updated lock file
+cd "$(dirname "${BASH_SOURCE[0]}")"
+npm i --package-lock-only @anthropic-ai/claude-code@"$version"
+rm -f package.json
+
+# Update version and hashes
+cd -
+nix-update claude-code --version "$version"