Integrate publish-documentation into release workflow; remove push auto-trigger

[Copilot]

publish-documentation.yml was firing automatically on every push to release/**, running independently from release.yml and outside the controlled release pipeline.

Changes

publish-documentation.yml

• Replaced push trigger with workflow_call — workflow is now exclusively driven by release.yml or manual dispatch
• workflow_dispatch retained for on-demand runs

release.yml

• Added publish-documentation job between pack and publish-package:
  • Depends on pack + validate-release
  • Gated with if: is-release == 'true' — skipped on preview/** branches
  • Calls ./.github/workflows/publish-documentation.yml with explicit pages: write + id-token: write permissions
• Updated publish-package to depend on publish-documentation with an always()-based condition to handle the skipped result on preview branches, preventing the gate from blocking NuGet publishing:

publish-package:
  needs: [pack, validate-release, publish-documentation]
  if: >-
    always() &&
    needs.pack.result == 'success' &&
    needs.validate-release.result == 'success' &&
    (needs.publish-documentation.result == 'success' || needs.publish-documentation.result == 'skipped')