Automatically collect e-signed Tax forms upon cash out request [$1000]

For any **year-to-date** cash out total of $600 or more, we need to collect a short tax form (w-8,w-9).

Current process:

- in cashout admin, I see the Y-t-D is >600
- using our helpdesk system (Groove), I email the user our template "Forms needed..." email
- manually check our email and wait for a completed form from PDFFiller
- user is now manually cleared for cash outs

What should happen:

~~1. If Y-t-D is >=600 USD, block cash out request attempts~~
1. If user is not flagged as "tax form complete" they will be required to fill out a form before they can request a cash out. This is for all users, not just >$600.
2. prompt user to select the appropriate form and fill it out
2. Eliminate the need for PDFFiller completely -- Is there an open project we can use that will give us valid form completion & e-signing?
3. upon e-sign, flag user as "Tax form complete".
4. user can now submit a cashout request
5. pdfs should be stored in a safe but accessible location for verification

Start by tracing the existing cash out request flow and the cash out admin view described in the issue. Determine where user tax-form status is stored and where completed forms could be safely accessed. Done means users are prompted for the appropriate form, completion is recorded after e-signing, cash out requests are gated correctly, and PDFs remain available for verification.

Written by the indexing model from the issue text.