[RFC] Different timestamp formats used in various collections within our repository

We have observed that different timestamp formats (Firestore Timestamp, Unix Timestamp, Epoch Timestamp) are being used inconsistently across collections in our repository. This inconsistency can lead to confusion and complexity when working with timestamps. To ensure consistency and simplify data management, we propose standardizing the timestamp format across all collections.

Proposed Solution:

1. Identify all collections that use different timestamp formats.
2. Determine the most appropriate timestamp format to use universally across collections (e.g., Firestore Timestamp, Unix Timestamp, ISO 8601).
3. Migrate the collections to use the chosen timestamp format consistently.
4. Update relevant code and queries to handle the new timestamp format.
5. Test and verify the changes to ensure proper functionality.
6. Document the standardized timestamp format and update relevant documentation.
7. By standardizing the timestamp format, we can improve maintainability, reduce potential errors, and enhance the overall consistency of our repository.

Start by inventorying the repository's collections and identifying where Firestore, Unix, and epoch timestamps are used. Decide on the universal timestamp format, then assess the required collection migrations, code and query updates, tests, and documentation changes. Done means all collections and related behavior use the chosen format consistently.