Feature: Evaluate and migrate Assets implementation to ERC-1155 usage

**What**

Evaluate the current Assets implementation and, where feasible, convert it to use ERC-1155 patterns and standards.

**Why**

Adopting ERC-1155 can improve support for multi-token asset models, reduce duplication in token handling logic, and align the Assets layer with a widely used standard for fungible/non-fungible hybrid use cases.

**How**

- Audit the current Assets implementation and identify ERC-721/other assumptions.
- Define the target ERC-1155 data model, interfaces, and compatibility boundaries.
- Implement ERC-1155-based contract and service changes for asset minting, transfers, and balance queries.
- Update related API/serialization/indexing paths to support ERC-1155 token IDs and balances.
- Add/adjust tests for minting, transfers, approvals, and edge cases (including batch flows where relevant).
- Document migration considerations and rollout/backward-compatibility constraints.

**Acceptance Criteria**

- A clear feasibility assessment is documented for converting Assets to ERC-1155.
- If feasible, Assets functionality is implemented on ERC-1155 and existing core flows continue to work.
- Automated tests cover the updated ERC-1155 behavior for Assets.
- Any migration constraints, compatibility impacts, and follow-up items are documented.

**Estimation**

**Dependencies**

None currently identified.

Start by auditing the current Assets implementation and its ERC-721 or other token assumptions, then map the minting, transfer, balance, API, serialization, and indexing flows. Define the ERC-1155 data model, interfaces, compatibility boundaries, and migration constraints before implementation. Done means a documented feasibility assessment, updated behavior and automated tests if feasible, plus rollout and follow-up documentation.

Written by the indexing model from the issue text.