github/workflows: Add per-class function coverage checks to CI

- Updated `test-and-publish.yml` with a new step to check class function
  coverage for `PdfRestClient` and `AsyncPdfRestClient`.
- Ensured minimum 90% coverage thresholds for specified classes.
- Configured Markdown reporting for detailed class function coverage data.

Assisted-by: Codex

Author: datalogics-kam

.github/workflows/test-and-publish.yml

@@ -48,6 +48,14 @@ jobs:
           --compare-branch origin/${{ github.base_ref }}
           --fail-under 90
           --markdown-report coverage/py${{ matrix.python-version }}/diff-cover.md
+      - name: Check client class function coverage
+        run: >
+          uv run python scripts/check_class_function_coverage.py
+          coverage/py${{ matrix.python-version }}/coverage.json
+          --class PdfRestClient
+          --class AsyncPdfRestClient
+          --fail-under 90
+          --markdown-report coverage/py${{ matrix.python-version }}/class-function-coverage.md
       - name: Upload coverage reports
         if: always()
         uses: actions/upload-artifact@v4