chore: .editorconfig + .nvmrc (Node 22), single-source Node version

.editorconfig

@@ -0,0 +1,13 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2
+
+# Markdown uses trailing whitespace for hard line breaks.
+[*.md]
+trim_trailing_whitespace = false

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v6
         with:
-          node-version: '20'
+          node-version-file: '.nvmrc'
           cache: 'npm'
 
       - name: Install dependencies

.github/workflows/publish.yml

@@ -23,7 +23,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v6
         with:
-          node-version: '20'
+          node-version-file: '.nvmrc'
           registry-url: 'https://registry.npmjs.org'
 
       # Trusted Publishing requires npm >= 11.5.1; Node 20 ships with npm 10.x.

.nvmrc

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