Streck account admin page

Should have an admin page where you easily can view streck accounts with options for filtering and sending emails.

A page for viewing streck accounts with:
- Filters for streck accounts (balance, recently active, etc.)
- Buttons for copying email address or sending mail.
- Maybe some more stuff idk I haven't thought a lot


Start by reviewing the existing Streck account and email-related flows to determine where an admin page would fit. Define the required filters, account actions, and any additional scope before implementation. Done means the page supports the agreed account views, filtering, email copying, and sending behavior.

Written by the indexing model from the issue text.