Clarify CONTRIBUTING.md (#3742)

.github/CONTRIBUTING.md

@@ -54,10 +54,9 @@ After forking this repository, you'll want to [create a branch](https://docs.git
 #### 3. Install dependencies and run the project locally
 
 ##### Prerequisites:
-- Node.js (Version: >= 22.3)
-  - Use `nvm` for easy Node management
-- [Bun](https://bun.sh/) (Version: >=1.2.15)
-  - We use a text-based lockfile which isn't supported below 1.2.15
+
+- [Node.js](https://nodejs.org/en) (see "engines" in `package.json`)
+- [Bun](https://bun.sh/) (see "packageManager" in `package.json`)
 
 ##### Setup steps:
 

package.json

@@ -1,6 +1,9 @@
 {
     "name": "gitbook",
     "version": "0.1.0",
+    "engines": {
+        "node": "^22.3.0"
+    },
     "devDependencies": {
         "@biomejs/biome": "^1.9.4",
         "@changesets/cli": "^2.29.7",