[codex] Add CSV workflow example

[Kkkakania]

This adds a clean-room CSV workflow example that connects the library to a common research workflow: taking a small CSV table and producing submission-check-ready figures.

What changed:

• Added examples/csv-workflow/sample_measurements.csv with synthetic measurement data.
• Added a Python renderer that exports PNG and PDF outputs from the CSV.
• Added a MATLAB renderer for the same CSV and figure structure.
• Added a Chinese README and a submission-check report template for self-auditing the exported figure.
• Linked the workflow from README.md and docs/quick_start.md so users can find the complete CSV path.

Why:

• This gives users a concrete "CSV to figure to submission check" path without introducing private data, paper screenshots, or binary assets.
• It supports the repository's clean-room boundary and connects naturally with matlab-figure-ci style figure QA.
• The change stays isolated under examples/csv-workflow/ except for small discoverability links in the main docs.

Validation:

• Ran the Python workflow with temporary matplotlib installed under /tmp/codex-spfl-mpl; it produced non-empty PNG and PDF outputs in /tmp/codex-spfl-csv-out.
• Ran py_compile on examples/csv-workflow/plot_csv_workflow.py.
• Ran scripts/check_publication_ready.py: passed.
• Ran scripts/check_release_state.py with temporary matplotlib on PYTHONPATH: passed.
• Ran scripts/check_matlab_syntax.py: scanned 1015 .m files, 0 issues.
• Ran python -m pytest tests/ with temporary matplotlib on PYTHONPATH: 1008 passed, 11 existing warnings.
• Ran git diff --check HEAD~1 HEAD: no whitespace errors.

Cleanup:

• Removed Python cache directories from the local checkout before committing.
• Temporary dependency/output directories under /tmp were used only for validation.