Add a command for converting between timestamp (closed at) and nearest ledger seq #2285
Description
What problem does your feature solve?
Many things work on ledger sequence numbers, but as humans we often think in real time.
Being able to look for a ledger seq around the time we know something happened would be helpful.
What would you like to see?
A command that accepts either a closed at timestamp or a ledger seq and returns the other component. For when converting from timestamp to ledger seq, it picks the closest ledger that happened just before the time.
How
Using the history archives to narrow down to a nearest checkpoint ledger (every 64th ledger), and then using the AWS Public Blockchain Dataset which has LedgerCloseMeta for every ledger in a separate file for narrowing down within that. Look at Simons implementation discussed at https://stellarfoundation.slack.com/archives/C02B04RMK/p1762974437297459?thread_ts=1762971384.670759&cid=C02B04RMK for inspiration.
What alternatives are there?
Not doing this.
Related conversation: https://stellarfoundation.slack.com/archives/C02B04RMK/p1762971384670759