Klever-Go KVM read-only execution can commit contract delete and upgrade side effects

Summary

Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.17, KVM exposes `ExecuteReadOnlyWithTypedArguments` as a read-only execution mechanism. The hook saves the previous read-only state, sets `runtime.SetReadOnly(true)`, executes the destination context, and then restores the previous read-only state. However, the indirect contract delete and upgrade paths do not reject execution when `runtime.ReadOnly()` is true. As a result, a contract reached through read-only execution can call the production delete hook for a target contract it owns. The delete path appends the target address to `vmOutput.DeletedAccounts`, the output context merges `DeletedAccounts` into the caller output, and the smart contract processor later processes the VM output by deleting accounts listed in that field. The root cause is that read-only mode is applied as runtime state, but not enforced by the state-changing delete and upgrade host-core paths. This breaks the expected isolation boundary for workflows that rely on read-only calls to inspect another contract without allowing that callee to produce state-changing VM output. The issue is fixed in v1.7.17. Contract delete and upgrade host-core paths now reject execution when `runtime.ReadOnly()` is true. The invariant is regression-tested for delete, upgrade, storage writes, value transfers, and any VM output field that can later mutate chain state.