[feature]: Accounts System for Multi User Wallet Support

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**Is your feature request related to a problem? Please describe.**

We are working on "Prediction Markets" and will be using taproot assets to issue and sell shares for the numerous events. When the user bets on an event, they are basically buying shares for that event. These shares will by owned by multiple users. At this point the only way to do this is in our own database. We need multi user Wallet/Accounts support on tapd.

**Describe the solution you'd like**

Accounts System:

A non-custodial way to create multiple user wallets/accounts on the same tapd instance. That way each user can self custody their assets in their own wallet.

**Describe alternatives you've considered**

Creating our own custodial accounting system database.

**Additional context**
N/A

Start by reviewing the tapd wallet and Taproot Assets architecture relevant to creating multiple user accounts on one instance. Define the non-custodial account model and boundaries first; done means multiple users can independently hold and self-custody assets without relying on an external custodial database.

Written by the indexing model from the issue text.