Add anonymization checks for shared example data

[Inkman007]

Advanced project-building issue

Level: Advanced
Scope: Significant repository capability work
Focus area: Add anonymization checks for shared example data

Goal

Improve Ledgerlens-data by adding a durable engineering capability, contract, validation path, or operational workflow. This issue should help move the project toward a more mature architecture, stronger contributor experience, and more reliable data and model workflows.

Contributor direction

• Start by identifying the affected modules, tests, configuration, fixtures, and CI entry points.
• Define the target contract or workflow before changing implementation details.
• Keep the solution reusable across related parts of the repo instead of solving only one narrow case.
• Preserve current public behavior unless the issue clearly requires a documented behavior change.
• Add diagnostics that make future failures actionable for maintainers.

Expected deliverables

• A concrete implementation or design-backed validation layer for the focus area.
• Tests, checks, fixtures, benchmarks, or developer commands that prove the behavior works.
• Clear integration with the existing repository structure and naming conventions.
• PR notes describing the design choice, validation run, and any follow-up risk.

Acceptance criteria

• The issue is solved at an advanced level, with enough depth for experienced contributors.
• The work improves the project foundation rather than only changing labels, comments, or surface formatting.
• Relevant tests or CI checks cover the new behavior and important failure modes.
• The implementation is maintainable, documented where needed, and avoids unrelated broad refactors.

[EngrEOOnoja]

I'd like to take this on. I'll start by mapping which modules and fixtures contain example data, then define a reusable anonymization-validation contract (detecting PII patterns like names, emails, account numbers) that plugs into existing CI checks, with clear diagnostics on failure and tests covering common leakage cases.