[KSlashh]

Audit item M23. Open against dev.

add_node_reward reads the node's reward, adds the increment in Rust and passes the new total to update_node_reward_by_peer_id, whose SQL then ran reward = reward + ?. Each reward event therefore added the old total again, so /v1/nodes showed a value that grew much faster than the real reward.

• update_node_reward_by_peer_id now stores the total it is given (reward = ?); the addition happens only in Rust. sqlx offline cache updated.

Tests: two rewards of 5 on a fresh node give 10 (15 before the fix). Node and store tests, clippy and fmt pass.

Validation results above are recorded in the zkm PR notes. Branch scope and diff formatting were checked locally; builds and tests were not rerun during publication.