chore: update minimum Node.js version to 18

- Update engines requirement to Node.js >=18.0.0 and npm >=9.0.0
- Update CI matrix to test Node.js 18, 20, and 22
- Remove EOL Node.js 16 from testing matrix
- Keep Dockerfile at Node.js 24 as updated by Dependabot

Node.js 16 reached end-of-life in September 2023 and no longer
receives security updates. Node.js 18 is the minimum active LTS.

Author: lainra

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [16.x, 18.x, 20.x]
+        node-version: [18.x, 20.x, 22.x]
 
     steps:
     - uses: actions/checkout@v4

package.json

@@ -47,8 +47,8 @@
   },
   "homepage": "https://github.com/lainra/claude-code-telemetry#readme",
   "engines": {
-    "node": ">=16.0.0",
-    "npm": ">=7.0.0"
+    "node": ">=18.0.0",
+    "npm": ">=9.0.0"
   },
   "files": [
     "src/",