Migrate to npm

Additionally:
- Add cooldown to dependabot configuration
- Remove tailwind ignore
- Add `.node-version` for parity with `.ruby-version`

Author: tagliala

.github/dependabot.yml

@@ -8,6 +8,8 @@ updates:
       github_actions:
         patterns:
           - "*"
+    cooldown:
+      default-days: 5
   - package-ecosystem: bundler
     directory: /
     schedule:
@@ -17,6 +19,8 @@ updates:
       bundler:
         patterns:
           - "*"
+    cooldown:
+      default-days: 5
   - package-ecosystem: npm
     directory: /
     schedule:
@@ -26,6 +30,5 @@ updates:
       npm:
         patterns:
           - "*"
-    ignore:
-      - dependency-name: "tailwindcss"
-        versions: ">= 4.0"
+    cooldown:
+      default-days: 5

.github/workflows/tests.yml

@@ -23,6 +23,10 @@ jobs:
         with:
           ruby-version: .ruby-version
           bundler-cache: true
+      - uses: actions/setup-node@v6
+        with:
+          node-version-file: .node-version
+          cache: npm
       - name: Run tests
         env:
           COVERAGE: true

.node-version

@@ -0,0 +1 @@
+lts/krypton

.npmrc

@@ -0,0 +1 @@
+ignore-scripts=true

Procfile.dev

@@ -1,2 +1,2 @@
 web: env RUBY_DEBUG_OPEN=true bin/rails server
-css: yarn build:css --watch
+css: npm run build:css -- --watch

README.md

@@ -11,7 +11,7 @@ https://activeadmin-demo.onrender.com
 - Install Node 24 with [nodenv](https://github.com/nodenv/nodenv)
 - `corepack enable`
 - `bundle install`
-- `yarn install`
+- `npm install`
 - `bin/rails db:seed`
 - `bin/dev`