chore: convert this repo from yarn to npm

Convert the repository from yarn to npm.

* **package.json**: Update scripts section to use npm commands instead of yarn.
* **.github/workflows/test.yml**: Update to use npm for installing dependencies and building the project.
* **.release-it.json**: Update after:bump hook to use npm run build instead of yarn build.
* **README.md**: Update instructions to use npm for installing dependencies instead of yarn.
* **package-lock.json**: Add new npm lockfile.

---

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.github/workflows/test.yml

@@ -20,10 +20,10 @@ jobs:
       - name: Setup Node
         uses: actions/setup-node@v4
         with:
-          cache: 'yarn'
+          cache: 'npm'
           node-version: 20
 
       - name: Install Node dependencies
-        run: yarn --frozen-lockfile
+        run: npm ci
 
-      - run: yarn build
+      - run: npm run build

.release-it.json

@@ -6,7 +6,7 @@
     "release": true
   },
   "hooks": {
-    "after:bump": "yarn build"
+    "after:bump": "npm run build"
   },
   "plugins": {
     "@release-it/conventional-changelog": {

README.md

@@ -64,7 +64,7 @@ console.log(cars);
 
 ## Development process
 
-Install dependencies with `yarn`.
+Install dependencies with `npm install`.
 
 ## Release process