internxt-cli v1.1.0 — within-file transfer concurrency

A single large file now transfers with bounded concurrency (multi-file batch concurrency via --workers already existed).

Added

• Parallel multipart part uploads (Step A): files ≥ 100 MiB upload their 30 MB S3 multipart parts in parallel (was sequential), bounded by the existing memory gate. AES-CTR encryption + content hash stay sequential; only the part PUTs overlap.
• Parallel ranged downloads (Step B, opt-in --ranged): large downloads fetch multiple HTTP byte-ranges concurrently, decrypt each via a seekable AES-CTR decryptor, and reassemble by offset. Falls back to single-stream when Range is unsupported or the file is small.

Preserved

• Batch file-level concurrency (--workers) unchanged; small files keep the single-PUT / single-GET path.

Unit tests + ruff + mypy + bandit gates green.