keccak256preimage tracer

[draganm]

Rationale

Problem

Prestate traces show storage slot changes but not the original mapping keys or array indices that generated those slots (since they're hashed). This makes debugging and analysis difficult.

Solution

Add a tracer that captures all keccak256 computations during transaction execution, allowing us to map hashed storage slots back to their original keys/indices.

Implementation

proposed implementation
#32569