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?