build: label pull requests from first-time contributors

---
type: pre_commit_static_analysis_report
description: Results of running static analysis checks when committing changes.
report:
  - task: lint_filenames
    status: passed
  - task: lint_editorconfig
    status: passed
  - task: lint_markdown
    status: na
  - task: lint_package_json
    status: na
  - task: lint_repl_help
    status: na
  - task: lint_javascript_src
    status: na
  - task: lint_javascript_cli
    status: na
  - task: lint_javascript_examples
    status: na
  - task: lint_javascript_tests
    status: na
  - task: lint_javascript_benchmarks
    status: na
  - task: lint_python
    status: na
  - task: lint_r
    status: na
  - task: lint_c_src
    status: na
  - task: lint_c_examples
    status: na
  - task: lint_c_benchmarks
    status: na
  - task: lint_c_tests_fixtures
    status: na
  - task: lint_shell
    status: na
  - task: lint_typescript_declarations
    status: na
  - task: lint_typescript_tests
    status: na
  - task: lint_license_headers
    status: passed
---

---
type: pre_push_report
description: Results of running various checks prior to pushing changes.
report:
  - task: run_javascript_examples
    status: na
  - task: run_c_examples
    status: na
  - task: run_cpp_examples
    status: na
  - task: run_javascript_readme_examples
    status: na
  - task: run_c_benchmarks
    status: na
  - task: run_cpp_benchmarks
    status: na
  - task: run_fortran_benchmarks
    status: na
  - task: run_javascript_benchmarks
    status: na
  - task: run_julia_benchmarks
    status: na
  - task: run_python_benchmarks
    status: na
  - task: run_r_benchmarks
    status: na
  - task: run_javascript_tests
    status: na
---

Author: Planeshifter

.github/workflows/labeler.yml

@@ -24,6 +24,7 @@ on:
   pull_request_target:
     types:
       - opened
+      - closed
       - synchronize
       - reopened
       - edited
@@ -64,6 +65,24 @@ jobs:
           configuration-path: .github/labeler.yml
           repo-token: ${{ secrets.CHATBOT_GITHUB_TOKEN }}
 
+      # Add "First-time Contributor" label if PR is from a first-time contributor:
+      - name: 'Add "First-time Contributor" label if PR is from a first-time contributor'
+        if: ${{ ( github.event.action == 'opened' || github.event.action == 'reopened' ) && github.event.pull_request.author_association == 'FIRST_TIME_CONTRIBUTOR' }}
+        # Pin action to full-length commit SHA
+        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
+        with:
+          github-token: ${{ secrets.CHATBOT_GITHUB_TOKEN }}
+          script: |
+            const labels = context.payload.pull_request.labels.map( label => label.name );
+            if ( !labels.includes( 'First-time Contributor' ) ) {
+              await github.rest.issues.addLabels({
+                'owner': context.repo.owner,
+                'repo': context.repo.repo,
+                'issue_number': context.payload.pull_request.number,
+                'labels': [ 'First-time Contributor' ]
+              });
+            }
+
       # Add "Needs Review" label when PR is opened and not a draft:
       - name: 'Add "Needs Review" label if PR is opened and not draft'
         if: ${{ github.event.action == 'opened' && github.event.pull_request.draft == false }}
@@ -133,3 +152,35 @@ jobs:
                 console.log( 'Error removing label %s: %s', label, error.message );
               }
             }
+
+      # Remove "First-time Contributor" label from other open PRs if PR is merged:
+      - name: 'Remove "First-time Contributor" label from other open PRs if PR is merged'
+        if: ${{ github.event.action == 'closed' && github.event.pull_request.merged == true }}
+        # Pin action to full length commit SHA
+        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
+        with:
+          github-token: ${{ secrets.CHATBOT_GITHUB_TOKEN }}
+          script: |
+            const prAuthor = context.payload.pull_request.user.login;
+
+            const { data: pullRequests } = await github.rest.pulls.list({
+              'owner': context.repo.owner,
+              'repo': context.repo.repo,
+              'state': 'open'
+            });
+
+            // Remove "First-time Contributor" label from any other open PRs by the same author:
+            for ( const pull of pullRequests ) {
+              if ( pull.user.login === prAuthor ) {
+                try {
+                  await github.rest.issues.removeLabel({
+                    'owner': context.repo.owner,
+                    'repo': context.repo.repo,
+                    'issue_number': pull.number,
+                    'name': 'First-time Contributor'
+                  });
+                } catch ( error ) {
+                  console.log( 'Error removing "First-time Contributor" label from PR #%d: %s', pull.number, error.message );
+                }
+              }
+            }