build: commit the lockfile and allow build: commits

The scaffold shipped with installs pinned to --package-lock=false, on a
misreading of AGENTS.md that has since been corrected. npm ci needs this file,
and npm ci is how every task worktree spins up.

Also adds 'build' to the commit-msg type list; it is a standard conventional
type and its absence rejected this very commit.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.husky/commit-msg

@@ -13,9 +13,9 @@ case "$first_line" in
   "Merge "*|"Revert "*) exit 0 ;;
 esac
 
-if ! printf '%s' "$first_line" | grep -qE '^(feat|fix|docs|refactor|chore|test|style|ci|perf)(\([a-z0-9 -]+\))?: .{1,}$'; then
+if ! printf '%s' "$first_line" | grep -qE '^(feat|fix|docs|refactor|chore|test|style|ci|perf|build)(\([a-z0-9 -]+\))?: .{1,}$'; then
   echo "commit-msg: subject must be '<type>: <subject>' (lowercase type)." >&2
-  echo "  types: feat fix docs refactor chore test style ci perf" >&2
+  echo "  types: feat fix docs refactor chore test style ci perf build" >&2
   echo "  got:   $first_line" >&2
   exit 1
 fi