Update Watchdog Bounty Structure Amid ARB Price Drop

ARB price dropped from $0.43 on October 14 to ~$0.11 on February 18, slashing Watchdog bounties: Low from $430 to $110, Medium from $2,150 to $550, High from $4,300 to $1,100. The recovery bonus rose from 5% to 15%. Bounties now USD-denominated: $200, $1