## Summary
Code mode has two separate truncation points: the nested tool result
returned to JavaScript and the code-mode output later recorded for the
model. These tests now verify those behaviors independently.
- Report whether `result.output` was truncated before printing it.
- Verify omitted or sufficiently large nested limits produce `Variable
truncated: False`, while allowing the printed value to be truncated
downstream.
- Verify an explicit nested limit produces `Variable truncated: True`
when the command output exceeds it.
- Use a token-policy model fixture so downstream truncation is visible
as `…N tokens truncated…`.
- Align the explicit nested-truncation expectation with the warning
header.
This PR changes test coverage only; runtime truncation behavior is
unchanged.
## Validation
- `env -u CODEX_SANDBOX_NETWORK_DISABLED RUST_MIN_STACK=8388608 cargo
test -p codex-core --test all code_mode_exec -- --nocapture` (8 passed)