Implement block-level transaction processing

[mw2000]

Summary

Process an entire block of transactions: execute each transaction sequentially, accumulate state, generate receipts, compute receipts trie root, and validate the final state root.

Specification

Block processing pipeline:

1. Execute system calls (beacon root deposit per EIP-4788, block hash storage per EIP-2935)
2. For each transaction in order:
   a. Execute via transaction pipeline
   b. Accumulate cumulative gas
   c. Generate receipt with cumulative gas
   d. Accumulate state changes
3. After all transactions:
   a. Compute state root from final state
   b. Compute receipts root from all receipts
   c. Compute transactions root from all txs
   d. Validate against block header

Prerequisites

• Transaction execution pipeline (issue)
• Receipt generation (issue)
• State root computation (issue)

Implementation Guide

1. Create lib/eevm/block/processor.ex — block processing orchestrator
2. process_block(block_header, transactions, pre_state_db) → {:ok, post_state_db, receipts} | {:error, reason}
3. Validate block gas limit — sum of tx gas must not exceed block gas limit
4. Execute system calls first if hardfork config enables them
5. Sequential transaction execution — each tx sees state from previous tx
6. Compute trie roots — state, receipts, transactions
7. Tests: single-tx block, multi-tx block, gas limit exceeded, system calls

Acceptance Criteria

• Processes all transactions in a block sequentially
• Cumulative gas tracked correctly
• State root matches expected after block processing
• Receipts root computed correctly
• Block gas limit enforced
• System calls executed at block start (when enabled)
• Tests pass

Reference

• Yellow Paper §11 (Block Finalization)
• execution-specs: process_block function