adding tests and then deploy

[akprinciple]

Description

This PR introduces the foundational Foundry test suite for the YieldSaveVault smart contract. It ensures the core functionality of the Phase 1 MVP operates securely and accurately integrates with Aave V3.

Key Changes

• Test Environment Setup: Configured YieldSaveVault.t.sol to use a Base Sepolia fork environment for accurate, deterministic Aave V3 integration testing.
• Constructor Validations: Added checks to ensure the vault reverts if initialized with zero addresses or if the fee rate exceeds the hard-coded cap (1000 BPS / 10%).
• Deposit Flow Tests: Verified share minting math, state updates (userShares, userDeposits), and zero-amount deposit reverts.
• Withdrawal Flow Tests: Verified net payout calculations, fee deductions, insufficient share reverts, and zero-amount withdrawal reverts.
• View & Preview Function Tests: Added comprehensive coverage for getVaultBalance, getUserBalance, previewWithdraw, and previewWithdrawFor (including edge cases for zero shares and non-existent users).

Type of Change

• New feature (non-breaking change which adds functionality)
• Test addition / enhancements