Refactor Health Record Schema to Support Unified Structure with Parent-Child Relationship

[AladinJmila]

The current MongoDB schema separates the main health record and its updates into two different Mongoose models. This task aims to refactor the schema to follow a more unified structure, similar to the SQL backend, where updates are treated as child records of a parent health record.

Requirements

• Merge the health record and update schemas into a single unified schema.
• Introduce an optional parentId field:
    - If parentId is null or undefined, the record is a top-level health record.
    - If parentId is set, the record is considered an update (child).
• Add an optional updates array to top-level records to store child record IDs.
• Ensure that only top-level records (i.e., those without a parentId) are allowed to have an updates array.
• Implement logic to prevent infinite nesting of updates (i.e., children cannot have their own updates arrays).
• Update any existing logic that fetches or processes updates to work with the new structure.

Notes

• This change is intended to align the MongoDB schema more closely with the SQL backend design.
• The updated structure should still support expansion of child records into full objects when queried.