Keycards: Three clearance reward levels

Keycards introduces a tiered reward model with three clearance levels.

Higher clearance levels grant larger rewards; priority and allocation mechanics are tied to clearance level.

The team states there will be more rewards on Testnet and Mainnet, meaning both environments will offer increased payouts compared to baseline.

A Discord community is provided for tracking roles and status (invite: https://discord.gg/dacchain). Roles and early role capture are highlighted as relevant for reward distribution.