SC: Set Up Soroban Environment for YieldForge

[Pvsaint]

Description: Configure the Soroban development environment to build and test smart contracts for the YieldForge stablecoin yield farm, ensuring compatibility with Stellar’s testnet.

Tasks:

Install Soroban CLI and Rust toolchain.
Set up a testnet environment for contract deployment.
Create a sample contract to verify setup (e.g., store user balance).

Acceptance Criteria:

Soroban CLI deploys a sample contract to Stellar testnet.
Sample contract is invoked successfully (e.g., stores/retrieves data).
Setup is documented in the repository.