Validate change-notes in PRs

This commit also introduces the 'empty' home directory for future change-notes.

.github/workflows/pr-checks.yml

@@ -114,6 +114,10 @@ jobs:
         working-directory: pr-checks
         run: npx tsx --test
 
+      - name: Run `pr-checks/changenotes.mts` to ensure that all unreleased change notes are valid
+        if: ${{ !cancelled() && steps.install-deps.outcome == 'success' }}
+        run: npx tsx pr-checks/changenotes.mts validate
+
       - name: Verify all Actions use the same Node version
         id: head-version
         run: |

pr-checks/config.ts

@@ -18,6 +18,9 @@ export const PACKAGE_JSON = path.join(REPO_ROOT, "package.json");
 /** The path of the changelog. */
 export const CHANGELOG_FILE = path.join(REPO_ROOT, "CHANGELOG.md");
 
+/** The path to the unreleased change-notes directory. */
+export const CHANGENOTES_DIR = path.join(REPO_ROOT, "unreleased-change-notes");
+
 /** The path to the esbuild metadata file. */
 export const BUNDLE_METADATA_FILE = path.join(REPO_ROOT, "meta.json");