ci: add PR title linting

.github/actions/lint-pr-title/.npmrc

@@ -0,0 +1,2 @@
+ignore-scripts=true
+omit-lockfile-registry-resolved=true

.github/actions/lint-pr-title/action.yml

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+name: lint-pr-title
+description: Ensure PR titles match the Conventional Commits Specification (https://www.conventionalcommits.org/).
+runs:
+  using: 'node24'
+  main: 'src/index.js'
+branding:
+  icon: 'shield'
+  color: 'green'

.github/actions/lint-pr-title/commitlint.config.mjs

@@ -0,0 +1,24 @@
+export default {
+  rules: {
+    'type-enum': [
+      2,
+      'always',
+      [
+        'feat',
+        'fix',
+        'docs',
+        'chore',
+        'build',
+        'refactor',
+        'test',
+        'ci',
+        'perf',
+        'revert',
+      ],
+    ],
+    'type-case': [2, 'always', 'lower-case'],
+    'type-empty': [2, 'never'],
+    'subject-empty': [2, 'never'],
+    'subject-full-stop': [2, 'never', '.'],
+  },
+};