Fix ArbGasInfoShim compliance: Selectors, Return Values, and Missing Methods

[steven3002]

This PR consolidates fixes for several critical bugs regarding the ArbGasInfoShim precompile compatibility. It aligns the shim implementation with the official Arbitrum ArbGasInfo interface, ensuring that function selectors, return values, and tuple mappings are correct for local development environments.

Related Issues

Closes #4
Closes #5
Closes #6
Closes #7

Changes Made

• Fixed Function Selectors (Issue Precompile uses wrong selectors #4): Corrected the precompile selector generation to match the official Arbitrum specification (e.g., ensuring getL1BaseFeeEstimate and getCurrentTxL1GasFees are recognized).
• Added Missing Methods (Issue ArbGasInfoShim missing standard ArbGasInfo methods #5): Implemented standard ArbGasInfo methods that were previously missing from the shim, preventing "function not found" errors in standard tooling.
• Aligned Return Values (Issue Bug: ArbGasInfoShim return values mismatch ArbGasInfo interface #6): Updated the return types to match the ArbGasInfo interface (returning uint256 where expected instead of incompatible types).
• Fixed Tuple Mapping (Issue Bug: nitroToShimTuple incorrectly maps ArbGasInfo return values #7): Patched the nitroToShimTuple logic to correctly map the return values from the internal emulation to the output buffer.

Verification

• Verified using scripts/validate-arbgas.js.
• Confirmed that getL1BaseFeeEstimate and getCurrentTxL1GasFees return valid values (0 for local dev) without reverting.
• Validated that the registry correctly identifies the updated function selectors.