feat: Report at certain dates

[floli]

Problem or use case

Hello!
I use beancount to have a (very coarse) tracking of my portfolio. Each month's first, I add a booking to account for wins/looses.
For that, I need the total valuation of my portfolio at a specific date. So far, I used the chart picker in the web UI.

Can I use the CLI tool to get the holdings at one point in time?

Proposed solution

e.g. have a additional parameter --at 2026-09-15 which accepts an ISO timestamp, where appropriate (broker holdings is a good first IMHO)

Alternatives considered

No response

Relevant command or workflow

No response

User impact

Important for my workflow.

Checklist

• I have searched existing issues.
• This is a CLI feature request, not an account/support request.
• I understand this repository is source-available and does not accept external PRs.