Implement Block Access List (BAL) processing for partial statefulness
per EIP-7928. This enables nodes to update state without re-executing
transactions by applying BAL diffs directly to the trie.
Key additions:
- ApplyBALAndComputeRoot: Core BAL processing with correct commit ordering
(storage trie → account Root → account trie)
- ProcessBlockWithBAL: Blockchain-level entry point for BAL processing
- HandlePartialReorg: Chain reorganization support using BAL history
- Comprehensive test coverage (31 tests):
* Unit tests for edge cases (storage deletion, EIP-161, buildStateSet)
* Blockchain integration tests (ProcessBlockWithBAL, HandlePartialReorg)
* Both HashScheme and PathScheme coverage
Devnet Testing (2-node setup):
- Full node: dev mode with --dev.period 2, creates blocks
- Partial node: --partial-state mode, syncs via P2P
- Test results: Block sync verified, balance queries match between nodes,
state roots consistent. Database size reduction observed for partial node.
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