Initialize the Incentives engine with an Admin
fn init(env: soroban_sdk::Env, admin: soroban_sdk::Address)
Set the authorized router (The only entity allowed to mint rewards)
fn set_router(env: soroban_sdk::Env, router: soroban_sdk::Address)
ABSOLUTE SECURITY: require_auth protects reward distribution
fn handle_action(
env: soroban_sdk::Env,
user: soroban_sdk::Address,
reward_amount: i128,
)