test2

Set BlockMajorVersion 10 upgrade height to 969696

- Add UPGRADE_HEIGHT_V10 = 969696 configuration
- Add m_upgradeHeightV10 member to Currency class
- Add upgradeHeightV10() builder method
- Add BLOCK_MAJOR_VERSION_10 case to upgradeHeight() method
- Configure upgrade height in Currency initialization

Enhanced privacy (ring size 8) will activate at block height 969696