1. check pending nonce and chain nonce before processing
2. check recently processed using local records before processing

1. Rename L2ContractEvent to BotDelegatedWithdrawal
2. Add unique constraint idx_bot_delegated_withdrawals_transaction_hash_log_index_key
3. Add new field `InitiatedBlockNumber int64` to indicate the L2 number
   of initiated withdrawal transaction
3. Add new fields `ProvenTime *Time` and `FinalizedTime *Time` to
   indicate the local time of L1 proven transaction and finalized
   transaction
4. Modify the `FailureReason` to type `FailureReason *string`

1. Determine the proven timing based on the `L2OutputOracle.latestBlockNumber`
2. Determine the finalized timing based on the db `proven_time`