test: order native socket setup and cancellation checks

[roodboi]

Two Rust socket tests configured or checked state before establishing the ordering they rely on. Configure the existing two-second read timeout before sending the half-close payload, and check dropped relay-command cancellation after the existing reactor liveness barrier. All payload, FIN, credential-refusal assertions and time budgets remain unchanged; production behavior is unchanged.

Validation: independent review of the exact two-file diff against current next; fresh default Rust suite (1,114 passed, 63 ignored, zero failures), both affected tests with all features, formatting, all-target default Clippy, and tracked-file privacy checks. Hosted CI remains required. The earlier hosted timeout-configuration EINVAL is recorded; its kernel cause is unproven.

Release intent: test-only ordering correction; no release or runtime behavior change.

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