docs: add a de-identification cookbook notebook with end-to-end recipes

[pardeep-singh]

Summary

Implements #316 (OM-151): adds a task-oriented de-identification cookbook of short, copy-paste recipes, filling the gap between the existing complete-guide notebooks and common workflow snippets.

examples/notebooks/Deidentification_Cookbook.ipynb covers four recipes with synthetic PHI only and cleared outputs:

1. De-identify a list or CSV of clinical strings with deidentify and stdlib csv.
2. Batch-redact a directory of .txt files via BatchProcessor(operation="deidentify").process_directory(...), writing redacted file copies.
3. Reversible replace + re-identify round-trip with deidentify(method="replace", keep_mapping=True, consistent=True) and reidentify(...).
4. Per-language model selection with DEFAULT_PII_MODELS.

The live examples use the lightweight 44M English PII model for CPU-friendly runs. Other language defaults are displayed but not executed to avoid larger downloads.

Changes

• examples/notebooks/Deidentification_Cookbook.ipynb — new cookbook with four task-oriented recipes.
• examples/notebooks/README.md — links the new cookbook.
• tests/unit/test_deidentification_cookbook.py — lightweight structural tests that validate JSON shape, four recipe sections, synthetic-data disclaimer, cleared outputs, key public API examples, and the batch recipe's redacted-file output path.

Acceptance criteria

• Notebook exists with the four recipe sections using synthetic data only.
• README links the new cookbook.
• Lightweight check confirms the notebook is valid JSON/structure.
• Test suite green: .venv/bin/python -m pytest tests/ -q -> 1622 passed, 1 skipped.

Notes

• The notebook's model-calling cells are not executed in CI, matching the issue's out-of-scope list.
• No new development dependency is required for the structural notebook test.

Out of scope

• FHIR/multimodal cookbooks, CI execution of full notebooks against live models, and replacing the existing complete-guide notebooks.

Closes #316

[pardeep-singh]

@maziyarpanahi Please have a look at this for #316 Issue

[maziyarpanahi]

Thanks @pardeep-singh for the contribution.

I pushed a follow-up commit (b4b5f02) that:

• makes the batch directory recipe write redacted output files, not just print results
• removes the unused import and trims the new cookbook/README wording
• changes the structural notebook test to use stdlib JSON validation, so no new development dependency or lockfile update is needed
• strengthens the test coverage for the expected public API snippets and redacted-output path

Verification:

• local .venv/bin/python -m pytest tests/ -q: 1622 passed, 1 skipped
• remote checks are green
• PR labels now match Add a de-identification cookbook notebook with end-to-end recipes #316
• merge state is clean

This is ready to merge and will close #316.