Grant GitHub Pages permissions in multi-branch publish workflow

[Copilot]

The multi-branch publish workflow was using a token scope that was too narrow for GitHub Pages setup, causing actions/configure-pages to fail with Resource not accessible by integration. This updates the workflow to use the standard Pages deployment permission set without changing render, branch, or deployment flow.

• Permission model

  • Replace the top-level workflow permission block with the explicit Pages scopes:
    • contents: read
    • pages: write
    • id-token: write

• Behavior preserved

  • Leave existing branch filtering, render commands, action SHAs, push-to-gh-pages flow, and concurrency controls unchanged.

• Workflow delta

  permissions:
    contents: read
    pages: write
    id-token: write