Fragmetric Liquid Restaking Program - 2

The `admin_create_user_reward_account_idempotent` instruction provides a privileged admin with the ability to create a `UserRewardAccount` on behalf of any user. When this instruction is called, it hardcodes the `FUND_MANAGER_PUBKEY` as a delegate for the new account. This is a significant trust assumption in the protocol, as it grants the Fund Manager authority over the user's reward account without the user's direct signature for the delegation. This functionality is likely intended for administrative or onboarding purposes, but it implies that users must trust the Fund Manager not to misuse these delegated privileges (e.g., claiming rewards on their behalf).

The reward update logic for a given user loops over all reward settlements, and for each reward settlement, it loops over all reward blocks to calculate the reward per block for the user. There can be multiple reward settlements with multiple reward blocks inside of them. For dormant or highly inactive users, the nested loops can cause the transaction to consume all computation units and revert, which will prevent the user from interacting with the protocol.