CVE-2026-75858: CodeWhale: rlm_eval auto-approves arbitrary Python execution, bypassing the user's approval policy (RCE)

The rlm_eval tool runs an arbitrary Python string chosen by the model in a real python3 interpreter. Its approval_requirement() returns ApprovalRequirement::Auto, which the engine treats as “never prompt,” regardless of the user’s configured --approval-policy. A single tool call — which prompt injection from any untrusted content the agent reads (a web page, a fetched URL, a repo file, an MCP tool result) can induce — runs code on the user’s machine at the user’s privilege with no prompt and no audit step. This is the same defect that was already patched on the sibling run_tests tool (CVE-2026-45311); the fix never reached rlm_eval or rlm_open, which expose a broader surface (full Python on the host, not just cargo test).