feat: implement gas optimization utilities and add GasGuard G014 rule

[lishmanTech]

Summary

This PR introduces several gas optimization improvements across the codebase, including low-level Yul optimizations, storage packing techniques, and a new GasGuard analysis rule.

Changes

Contracts

• Implemented a zero-allocation ERC-20 permit processor using inline Yul assembly.
• Added a compact packed storage map that stores up to 32 uint8 values in a single bytes32 storage slot.
• Implemented a scratch-space Keccak hasher that computes hashes using memory locations 0x00 and 0x20, eliminating unnecessary memory allocation.

Gas Optimizations

• Eliminated dynamic memory allocation for permit calldata construction.
• Reduced storage operations by replacing fixed-size mappings with bit-packed storage.
• Optimized hashing by utilizing EVM scratch memory and avoiding free memory pointer expansion.

GasGuard

• Added Rule G014 to detect uncached storage array .length accesses inside loops and conditional statements.
• Emits actionable diagnostics recommending caching storage array lengths in local variables.
• Excludes memory and calldata array length accesses from detection.

Testing

• Added unit tests covering the new contract implementations.
• Added fixtures validating the new GasGuard rule.
• Included gas comparison benchmarks where applicable.

Closes

Closes #683
Closes #684
Closes #687
Closes #689

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