chore(package): pin supported Node range + CI matrix (#432) (#445)

No engines field existed anywhere, and npm install failing on Node 24 has
bitten users before (closed #11). Newer local Node has also hidden crashes
that the CI Node-20 baseline caught.

- engines: node >=20.18.0 <25.0.0, npm >=10 in root + server + client
- .nvmrc pinned to 22 (current LTS) so 'nvm use' picks a supported line
- CI now runs the test+build matrix on Node 20 and 22 (fail-fast off)

No .npmrc engine-strict, so the engines field stays advisory and does not
break installs for anyone already on a working version.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -8,14 +8,21 @@ on:
 
 jobs:
   test:
-    name: Test & build
+    name: Test & build (Node ${{ matrix.node-version }})
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        # Both ends of the supported engines range (package.json: >=20.18 <25).
+        # 20 is the CI baseline that has historically caught crashes newer local
+        # Node versions hid; 22 is the current LTS most contributors run.
+        node-version: ['20', '22']
     steps:
       - uses: actions/checkout@v4
 
       - uses: actions/setup-node@v4
         with:
-          node-version: '20'
+          node-version: ${{ matrix.node-version }}
           cache: 'npm'
 
       - name: Install dependencies

.nvmrc

@@ -0,0 +1 @@
+22

client/package.json

@@ -45,5 +45,9 @@
     "typescript": "~6.0.2",
     "typescript-eslint": "^8.58.0",
     "vite": "^8.0.4"
+  },
+  "engines": {
+    "node": ">=20.18.0 <25.0.0",
+    "npm": ">=10.0.0"
   }
 }

package.json

@@ -24,5 +24,9 @@
   },
   "devDependencies": {
     "concurrently": "^9.1.2"
+  },
+  "engines": {
+    "node": ">=20.18.0 <25.0.0",
+    "npm": ">=10.0.0"
   }
 }

server/package.json

@@ -40,5 +40,9 @@
     "tsx": "^4.19.4",
     "typescript": "^5.8.3",
     "vitest": "^3.1.3"
+  },
+  "engines": {
+    "node": ">=20.18.0 <25.0.0",
+    "npm": ">=10.0.0"
   }
 }