ci: trigger website rebuild on release

[ByteYue]

Description

When a new version is released (v* tag push), trigger the opencli-website to rebuild via repository_dispatch. This ensures the website always displays the latest released version number.

Reuses the existing WEBSITE_DEPLOY_TOKEN secret (already used by docs.yml).

Companion PR: jackwener/opencli-website#1

Type of Change

• 🔧 CI / build / tooling

Checklist

• I ran the checks relevant to this PR
• I updated tests or docs if needed
• I included output or screenshots when useful

Screenshots / Output

# New step added to release.yml:
- name: Trigger website rebuild
  uses: peter-evans/repository-dispatch@v3
  with:
    token: ${{ secrets.WEBSITE_DEPLOY_TOKEN }}
    repository: jackwener/opencli-website
    event-type: version-released