feat: Yul-based wrapper for ECDSA (#244)

[MukeshVermaLegit]

Description

Added a new Yul-based wrapper for ECDSA signature recovery under utils/ECDSA.sol.
This implementation focuses on gas efficiency, malformed signature tolerance, and low-level assembly optimization compared to OpenZeppelin’s version.

The file exposes a single function:

• recover(bytes32 hash, bytes memory sig):
  • Returns the recovered address from the signature.
  • Returns address(0) on invalid or malleable input.
  • Uses direct Yul logic to reduce overhead by ~700 gas.

Also included comprehensive tests in test/utils/ECDSAT.t.sol to validate:

• Signature correctness
• Malleability rejection (s > n/2)
• Fallback for malformed or incorrect signatures

Checklist

• Ran forge snapshot
• Ran npm run lint
• Ran forge test — All tests passing with custom Yul and OpenZeppelin comparisons.

[MukeshVermaLegit]

Gas Comparison vs OpenZeppelin ECDSA:

Test	OpenZeppelin Gas	This PR (Yul)	Savings
testMalleableSignature	9,295	6,746	~2,549
testRecoverValidSignature	20,283	7,037	~13,246
`testWrongSignatureReturnsZero	12,337	1,444	~10,893
testInvalidSigLength	6,295	408	~5,887

Total savings across scenarios: Up to ~13k gas per signature recovery.