Spitfire - migrate to shared CI workflows

Summary: Use shared workflow templates from folio-org/.github instead of local copies.

Details: Loosely copying the shared workflow repo’s excellent UI README, which contains additional configuration options:

1. Open a PR that replaces the .github/workflows/build-npm.yml and .github/workflows/build-npm-release.yml files with a single file, .github/workflows/ui.ymlwith the following content:

   name: Centralized workflow on: - push - pull_request - workflow_dispatch jobs: ui: # Use the shared workflow from https://github.com/folio-org/.github uses: folio-org/.github/.github/workflows/ui.yml@v1 # Only handle push events from the main branch or tags, to decrease PR noise if: github.ref_name == github.event.repository.default_branch || github.event_name != 'push' || github.ref_type == 'tag' secrets: inherit

2. In the PR body, tag members of the infrastructure-frontend team who have the necessary GH privileges to change the PR merge requirements. They will turn off the steps from the old workflows and turn on those from the new workflows.

3. Merge the PR.

4. Profit!!!