backup-state and restore-state subcommands to use bonsai

[macfarla]

PR description

Both BackupState.java and RestoreState.java explicitly cast the world state archive to ForestWorldStateArchive and use Forest-specific APIs (trie traversal via StoredMerklePatriciaTrie.visitLeafs, PersistVisitor/RestoreVisitor for trie reconstruction). Since
Forest is deprecated and Bonsai is the default, thus these commands are effectively broken for all default-configuration nodes.

Proposed Fix

Replace Forest world state access with Bonsai flat DB APIs:

• Backup: Use BonsaiWorldStateKeyValueStorage.streamFlatAccounts() and streamFlatStorages() to iterate accounts and storage instead of Forest trie traversal
• Restore: Use BonsaiWorldStateKeyValueStorage.Updater.putAccountInfoState(), putCode(), and putStorageValueBySlotHash() to write flat DB entries instead of Forest trie reconstruction
• Backup file format: Unchanged — the RLP structure ([accountHash, accountRlp, code] + storage entries + empty-list terminator) remains the same

Fixed Issue(s)

fixes #9811

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• Checked out our contribution guidelines?
• Considered documentation and added the doc-change-required label to this PR if updates are required.
• Considered the changelog and included an update if required.
• For database changes (e.g. KeyValueSegmentIdentifier) considered compatibility and performed forwards and backwards compatibility tests

Locally, you can run these tests to catch failures early:

• spotless: ./gradlew spotlessApply
• unit tests: ./gradlew build
• acceptance tests: ./gradlew acceptanceTest
• integration tests: ./gradlew integrationTest
• reference tests: ./gradlew ethereum:referenceTests:referenceTests
• hive tests: Engine or other RPCs modified?

[macfarla]

Re the failing AcceptanceTest: the test data archive is a Forest-format database, but our code now requires Bonsai. The checkArgument(worldStateArchive instanceof BonsaiWorldStateProvider, ...) fails when the node starts with Forest data.
this test does a full backup → restore → re-backup round-trip. The failure is because:

1. The test data archive (version1/besu-db-archive.tar.gz) contains a Forest-format database
2. The test framework defaults to DEFAULT_FOREST_CONFIG
3. Our code now requires BonsaiWorldStateProvider, so the checkArgument fails and the backup node exits with code 1

The chain data (blocks, headers, receipts) is format-agnostic, but the world state in the archive is stored as Forest trie nodes, which a Bonsai-configured node can't read.

Options:

1. Generate a new Bonsai test data archive — replace version1/besu-db-archive.tar.gz with one containing a Bonsai DB. This requires running a node to create it.
2. Restructure the test — instead of using a pre-built archive, have the test create a fresh Bonsai node in dev mode, mine some blocks, then test backup/restore on that. This eliminates the dependency on Ropsten data.
3. Support both formats — detect whether the world state is Forest or Bonsai and use the appropriate APIs. This adds complexity but keeps backward compatibility.

[macfarla]

closing this since the fact this is still on forest is clear indication it's not being used. will remove in a new PR