data/ + schemas/: Add unit tests + fixtures (searchability / indexing)

[Gbangbolaoluwagbemiga]

Problem

This work item hardens data/ + schemas/ in the area of searchability / indexing so the project can
scale in production (reliable CI, predictable outputs, and safe-by-default behavior).

Work

• Identify the owner modules/files inside data/ + schemas/ for searchability / indexing.
• Implement the change described by Add unit tests + fixtures with minimal breaking surface.
• Add tests (unit + integration where relevant) and ensure they run in CI.
• Update docs/examples so contributors can adopt the new behavior confidently.

Acceptance criteria

• CI passes for the touched area (lint, tests, and any component-specific workflow).
• Behavior is documented (link from DOCUMENTATION_INDEX.md or the nearest canonical doc).
• Output formats remain stable; if changes are required, version bump + migration notes are included.

Notes

Component: data/ + schemas/
Subarea: searchability / indexing
If this expands beyond a single PR, split into sub-issues and cross-link.