Fix incentive simulation to correctly calculate total payout

Adjusted IncentiveSimulation.tsx to use a fixed participation number (20) and calculate estimated total payout by multiplying base rate by fixed participation, rather than using a 24-hour payout calculation.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 6130ed3f-1383-4699-bfde-0055e61d3a20
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/db94a198-a65c-4a53-a11c-15b472ffe527/6130ed3f-1383-4699-bfde-0055e61d3a20/IGFXC6U
