SCANNPM-132 docs: Add Sonar Update Center release process (#398)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: vdiez

docs/DEV.md

@@ -90,3 +90,31 @@ You can test the release workflow without actually publishing by using the manua
    - **Simulate [skip-latest]**: Check to test the skip-latest behavior
 
 The workflow will run and display the npm tag that would be used without performing any actual build or publish operations.
+
+### Sonar Update Center
+
+After publishing a new release, the [Sonar Update Center](https://xtranet-sonarsource.atlassian.net/wiki/spaces/DOC/pages/3385294896/The+Sonar+Update+Center) needs to be updated. This makes release information available at `downloads.sonarsource.com` for documentation and tooling.
+
+#### Update Process
+
+1. **Create a PR** in [sonar-update-center-properties](https://github.com/SonarSource/sonar-update-center-properties) to update `scannernpm.properties`
+
+2. **Add the new version entry** with the following format:
+
+   ```properties
+   X.Y.Z.description=Short description of the release
+   X.Y.Z.date=YYYY-MM-DD
+   X.Y.Z.changelogUrl=https://github.com/SonarSource/sonar-scanner-npm/releases/tag/X.Y.Z
+   X.Y.Z.downloadUrl=https://www.npmjs.com/package/@sonar/scan/v/X.Y.Z
+   ```
+
+3. **Update version lists**:
+   - Move the previous public version to `archivedVersions`
+   - Set the new version in `publicVersions`
+
+4. **After PR is merged**, run the scanner release notes GitHub Action on the [SonarQube-Documentation](https://github.com/SonarSource/SonarQube-Documentation) repo to create a PR that pushes the update to product docs
+
+#### Reference
+
+- Initial setup PR: [sonar-update-center-properties#742](https://github.com/SonarSource/sonar-update-center-properties/pull/742)
+- Published JSON: `https://downloads.sonarsource.com/sonarqube/update/scannernpm.json`