Promote drupal-contrib picker from staging to production

[rfay]

Context

The drupal-contrib template was merged with the new unified Drupal Issue Picker living at docs/drupal-contrib-picker.html (beta) while docs/drupal-issue.html was left as the original core-only picker.

The beta picker currently defaults to staging-coder.ddev.com so testers don't accidentally hit production.

What needs to happen when drupal-contrib is promoted to production

1. Replace docs/drupal-issue.html with the unified picker

   • Copy docs/drupal-contrib-picker.html → docs/drupal-issue.html
   • Change CODER_BASE default from https://staging-coder.ddev.com → https://coder.ddev.com
   • Update the comment above it (currently says "Beta picker — defaults to staging")
   • Update <title> from Drupal Issue Picker (Beta) → Drupal Issue Picker
   • Remove the BETA badge from <h1> and the staging warning from the subtitle
   • Update the sign-in link from staging-coder.ddev.com/login → coder.ddev.com/login

2. Remove docs/drupal-contrib-picker.html

   • It becomes redundant once drupal-issue.html is the unified picker

3. Update docs/index.html

   • Remove the beta card (the green "Open Beta Picker" card)
   • Update the original "Drupal Issue Picker" card description to mention contrib support

4. Push the drupal-contrib template to production Coder

   make push-template-drupal-contrib

5. Verify

   • Open start.coder.ddev.com/drupal-issue and confirm it routes core issues to drupal-core and contrib issues to drupal-contrib on coder.ddev.com
   • Test a contrib workspace end-to-end on production