Scaffold PDF preview and Copilot instructions in generated book projects

[Copilot]

Generated book repositories were missing two pieces of repo automation expected by the issue: a PR PDF preview workflow and a repository-specific Copilot instructions file. This change extends write new so newly scaffolded projects include both, with title- and project-specific substitutions applied at generation time.

• Scaffolded GitHub automation

  • Adds a generated /.github/workflows/pdf_preview.yml for book repos.
  • Preserves the repo’s existing PR preview behavior: build main.tex, upload a SHA-suffixed PDF artifact, and post/update a PR comment with the preview link.
  • Substitutes the generated project slug into artifact naming so each book repo gets correctly named preview output.

• Generated Copilot instructions

  • Adds /.github/copilot-instructions.md to generated projects.
  • Templates the book title and author into the instructions body so the generated repo starts with repository-specific guidance rather than a generic placeholder.

• Consistent template substitution

  • Moves generated author usage onto the same template replacement path as title substitution.
  • Applies the author value consistently in main.tex, book.toml, and the new Copilot instructions file.

• Scaffold contract updates

  • Updates the generated project tree snapshot and focused scaffold tests to cover the new files and substitutions.
  • Refreshes the README’s auto-generated structure block to reflect the expanded scaffold.

Example of the new generated workflow naming:

- name: Rename PDF with commit SHA
  run: mv main.pdf the-verse-awakens-${GITHUB_SHA}.pdf

- name: Upload PDF artifact
  with:
    name: 'the-verse-awakens-${{ github.sha }}.pdf'
    path: 'the-verse-awakens-${{ github.sha }}.pdf'

• Fixes Add automation tools to generated projects #71

[demccormack]

@copilot I forgot we already have build.yml doing some of this. So remove the new workflow and adapt build.yml to my requirements. Here is an example of how it should look if the new book was called "The Verse Awakens":

name: Build LaTeX PDF

on:
  push:
    branches: [main]
  pull_request:
  workflow_dispatch:

jobs:
  build:
    runs-on: ubuntu-latest
    permissions:
      contents: write
      pull-requests: write

    steps:
      - name: Checkout repository
        uses: actions/checkout@v7

      - name: Setup LaTeX
        uses: xu-cheng/latex-action@v4
        with:
          root_file: main.tex

      - name: Rename PDF with commit SHA
        run: mv main.pdf the-verse-awakens-${{ github.sha }}.pdf

      - name: Upload PDF preview artifact
        id: upload-pdf
        uses: actions/upload-artifact@v7
        with:
          name: the-verse-awakens-${{ github.sha }}.pdf
          path: the-verse-awakens-${{ github.sha }}.pdf
          archive: false

      - name: Add PDF preview to PR
        if: github.event_name == 'pull_request'
        uses: actions/github-script@v9
        env:
          ARTIFACT_URL: ${{ steps.upload-pdf.outputs.artifact-url }}
          PR_HEAD_SHA: ${{ github.event.pull_request.head.sha }}
          MERGE_SHA: ${{ github.sha }}
        with:
          script: |
            const marker = '<!-- pdf-preview -->';
            const headSha = process.env.PR_HEAD_SHA;
            const mergeSha = process.env.MERGE_SHA;

            const body = `${marker}
            ### 📖 PDF Preview

            **[Open PDF preview ↗](${process.env.ARTIFACT_URL})**

            Includes PR commit ${headSha.substring(0, 7)}  
            Built from merge commit ${mergeSha.substring(0, 7)}`;

            const comments = await github.paginate(github.rest.issues.listComments, {
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number,
            });

            const existingComments = comments.filter(
              comment =>
                comment.user.type === 'Bot' &&
                comment.body.includes(marker)
            );

            for (const comment of existingComments) {
              await github.rest.issues.deleteComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: comment.id,
              });
            }

            await github.rest.issues.createComment({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number,
              body,
            });

      - name: Create Release (on tag)
        if: startsWith(github.ref, 'refs/tags/')
        uses: softprops/action-gh-release@v3
        with:
          files: the-verse-awakens-${{ github.sha }}.pdf
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

[Copilot]

@copilot I forgot we already have build.yml doing some of this. So remove the new workflow and adapt build.yml to my requirements. Here is an example of how it should look if the new book was called "...

Addressed in 2a8e8ee. The generated build.yml now carries the PDF preview/upload/comment logic with the project slug substituted, and the separate pdf_preview.yml scaffold has been removed.

[github-actions]

📖 PDF Preview

Open PDF preview ↗

Includes PR commit 2a8e8ee
Built from merge commit 60da153