chore: add lint-staged with pre-commit hooks for src/ directory (#18)

* feat: add lint-staged with pre-commit hooks for src/ directory

- Add husky (9.1.7) and lint-staged (16.2.3) dependencies
- Configure lint-staged to run eslint and prettier on src/**/*.{ts,tsx} files
- Add pre-commit hook to run lint-staged
- Add post-checkout hook to run yarn install
- Add pre-push hook to prevent direct pushes to main
- Add .venv to .prettierignore to fix lint:check

* fix: use jlpm instead of yarn in husky hooks

- Update pre-commit hook to use 'jlpm exec lint-staged'
- Update post-checkout hook to use 'jlpm install'
- Aligns with jupyterlab-deepnote's package manager setup

* fix: remove packageManager field from package.json

The packageManager field was automatically added by yarn during
initial development but should not be present since jupyterlab-deepnote
uses jlpm (JupyterLab's yarn wrapper) for package management.

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

Author: jamesbhobbs

.husky/post-checkout

@@ -0,0 +1 @@
+jlpm install

.husky/pre-commit

@@ -0,0 +1 @@
+jlpm exec lint-staged

.husky/pre-push

@@ -0,0 +1,5 @@
+branch_name="$(git symbolic-ref --short HEAD)"
+if [ "$branch_name" = "main" ]; then
+  echo "Pushing directly to main is not allowed."
+  exit 1
+fi

.prettierignore

@@ -4,3 +4,4 @@ node_modules
 **/package.json
 !/package.json
 jupyterlab_deepnote
+.venv

package.json

@@ -47,6 +47,7 @@
         "install:extension": "jlpm build",
         "lint": "jlpm stylelint && jlpm prettier && jlpm eslint",
         "lint:check": "jlpm stylelint:check && jlpm prettier:check && jlpm eslint:check",
+        "prepare": "husky",
         "prettier": "jlpm prettier:base --write --list-different",
         "prettier:base": "prettier \"**/*{.ts,.tsx,.js,.jsx,.css,.json,.md}\"",
         "prettier:check": "jlpm prettier:base --check",
@@ -83,7 +84,9 @@
         "eslint": "^8.36.0",
         "eslint-config-prettier": "^8.8.0",
         "eslint-plugin-prettier": "^5.0.0",
+        "husky": "9.1.7",
         "jest": "^29.2.0",
+        "lint-staged": "16.2.3",
         "mkdirp": "^1.0.3",
         "npm-run-all2": "^7.0.1",
         "prettier": "^3.0.0",
@@ -98,6 +101,12 @@
         "typescript": "~5.8.0",
         "yjs": "^13.5.0"
     },
+    "lint-staged": {
+        "src/**/*.{ts,tsx}": [
+            "eslint --cache --fix",
+            "prettier --write"
+        ]
+    },
     "sideEffects": [
         "style/*.css",
         "style/index.js"