The translate package had no tests. These are fully hermetic: callOneshot is exercised against httptest, so go test ./... stays offline and fast.
Covers lang resolution (incl. the EN/PT target-vs-source asymmetry), TranslateByDeepLX preflight validation (404/400/413, pre-network only), callOneshot request shaping and gzip/deflate/br decoding, newInstanceID UUIDv4 shape, and the oneshotRequest JSON contract.
