Fix/scan without coin transfer

[longhoangwkm]

Add network-level coin transfer scanning flag

Problem

Some blockchain networks don't have coin transfer events registered, causing unnecessary trace_block RPC requests and "Coin transfer events not found" errors during block scanning.

Solution

• Added is_scan_coin_transfers boolean flag to networks table (default: true)
• Modified ProcessedBlockService to conditionally skip _processCoinTransferEvents() when flag is false
• Maintained backward compatibility with existing networks (default enabled)

Changes

• Migration: AddIsScanCoinTransfersToNetworks1734336000000
• Entity: NetworkEntity.is_scan_coin_transfers
• Service: Conditional coin transfer processing in scanBlock()
• Tests: 3 new unit tests covering enabled/disabled/default scenarios

Impact

• ✅ Reduces unnecessary RPC calls for networks without coin transfers
• ✅ Eliminates error noise in logs
• ✅ No breaking changes - defaults to existing behavior