feat: support concurrent chunk uploads

[TorstenDittmann]

This PR updates the SDK to support concurrent chunk uploads.

[greptile-apps]

Greptile Summary

This PR replaces the sequential chunked-upload loop with a bounded concurrent worker pool (up to 8 in-flight requests) for both the Node.js InputFile path and the browser File path. The first chunk is sent alone to obtain the server-assigned upload ID; subsequent chunks are dispatched through a shared queue that up to 8 async workers drain in parallel.

• The worker pool pattern is correctly coordinated through JavaScript's single-threaded event loop — queue.shift() is always called synchronously before the next await, so no TOCTOU issue exists on the shared queue.
• Both upload paths contain a dead-code if (totalChunks === 1) guard that can never be reached because the earlier size <= CHUNK_SIZE early-return already handles that case.
• The ping() return type was changed from Promise<string> to Promise<unknown> — an unrelated breaking TypeScript API change.

Confidence Score: 3/5

The concurrent upload rewrite has known unresolved correctness issues in both upload paths that warrant a fix before merging.

Two distinct issues flagged in earlier review rounds remain unaddressed in this diff: workers are not cancelled when the first failure occurs, and the fallback return value can silently be a stale first-chunk response. Both affect the core upload path and appear in both the InputFile and browser File code paths.

src/client.ts — both the InputFile and browser File worker-pool sections need attention for the error-propagation and return-value fallback concerns raised in the prior review threads.

Important Files Changed

Filename

Overview

src/client.ts

Rewrites the chunked-upload logic for both InputFile and browser File paths to use a concurrent worker pool (up to 8 parallel requests). Unresolved concerns from prior review threads (zombie workers after the first failure, and stale lastResponse fallback) are still present; new in this review: unreachable totalChunks === 1 guards in both paths and an unrelated breaking narrowing of ping() return type.

_{Reviews (4): Last reviewed commit: "feat: support concurrent chunk uploads" | Re-trigger Greptile}