chore: migrate husky to v9 configuration

The `husky install` command is deprecated in v9. Replace with the new
`husky` command and remove v8 artifacts (husky.sh sourcing, _/ directory).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Raymond Feng <enjoyjava@gmail.com>

Author: raymondfeng

.husky/.gitignore

@@ -1,6 +1,3 @@
-#!/usr/bin/env sh
-. "$(dirname -- "$0")/_/husky.sh"
-
 [ -n "$CI" ] && exit 0
 
 npx --no -- commitlint --edit "$1"

.husky/commit-msg

@@ -1,6 +1,3 @@
-#!/usr/bin/env sh
-. "$(dirname -- "$0")/_/husky.sh"
-
 [ -n "$CI" ] && exit 0
 if [ "$LINT_STAGED" = "0" ]; then
   echo "lint-staged disabled via LINT_STAGED env var"

.husky/pre-commit

@@ -6,7 +6,7 @@
   "copyright.owner": "IBM Corp. and LoopBack contributors",
   "repository": "github:loopbackio/loopback-next",
   "scripts": {
-    "prepare": "husky install",
+    "prepare": "husky",
     "postinstall": "npm run update-ts-project-refs",
     "update-ts-project-refs": "node bin/update-ts-project-refs.js",
     "prerelease": "npm run build:full && cross-env CI=1 npm run mocha && npm run lint",