chore: add pnpm + oxfmt for repo formatting

Pins Node 24 via .node-version, declares pnpm 10.32.1 as packageManager
in package.json, and adds oxfmt as a dev dependency with .oxfmtrc.json
(single quotes, no semi, 80 cols). Ignores node_modules.

package.json

@@ -0,0 +1,16 @@
+{
+  "name": "typewriter",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "packageManager": "pnpm@10.32.1",
+  "devDependencies": {
+    "oxfmt": "^0.49.0"
+  }
+}