Feature: Pre-built Emergency Address Freeze Hardfork

## Summary

Chains using Reth lack ready-to-deploy tooling for freezing wallet activity during active exploits. This issue proposes a pre-tested hardfork template that can restrict token transfers from arbitrary addresses with minimal configuration.

## Problem

When an exploit occurs, engineering teams must build and test address-freezing logic under time pressure. This introduces risk of mistakes and extends chain downtime. A pre-built solution would let teams respond faster and with more confidence.

## Proposed Solution

### 1. Emergency Freeze Hardfork Template

A tested, documented hardfork module that can:

- Freeze native token, ERC20, and ERC721 movement from a configurable address list
- Allow transfers only to a designated rescue address
- Deploy with config-only changes (no code modifications required)
- Include pre-written tests for all freeze scenarios

**Implementation locations:**

- **Block validation** (`validate_post_block_execution`): Reject blocks containing prohibited transfers by inspecting receipt logs for `Transfer` events
- **Block building** (commit conditions): Prevent validators from proposing invalid blocks

### 2. Oracle-based Address Blocklist (Exploratory)

Investigate mechanisms to freeze addresses without chain downtime:

**Option A:** Consensus client maintains a blocklist oracle, injected into execution client via Engine API

**Option B:** Authorized oracle submits blocked addresses to an on-chain contract, read during post-block execution

Trade-offs to consider:
- Race condition risk (attacker may transact before rules update)
- Decentralization implications of authorized oracles
- Effectiveness depends on control over block builders

## Acceptance Criteria

- [ ] Emergency freeze hardfork template with configurable address list
- [ ] Coverage for native token, ERC20, and ERC721 transfers
- [ ] Kurtosis-based test suite validating freeze behavior
- [ ] Deployment documentation
- [ ] (Optional) Evaluation of oracle-based approach

## References

- Berachain's $12M Balancer V2 exploit recovery used this approach successfully: https://x.com/RezMah/status/1989172438031122499