feat: add upload progress callbacks for queue API

[tomershlasky]

Summary

Adds upload progress tracking to the Queue API so callers can show real-time upload progress (e.g., a progress bar) when submitting large video files.

Upload Progress Callbacks

• New UploadProgressListener fun interface in QueueTypes.kt — a single onProgress(bytesWritten, totalBytes) callback
• New optional onUploadProgress parameter on all three submission methods:
  • submit(model, input, onUploadProgress)
  • submitAndPoll(model, input, onStatusChange, onUploadProgress)
  • submitAndObserve(model, input, onUploadProgress)
• Implemented via ProgressRequestBody — a standard OkHttp pattern that wraps the multipart body with a ForwardingSink counting bytes as they're written to the network
• totalBytes is the full multipart content length when known, or -1 for InputStream inputs where size is unknown
• All parameters are optional with null default — fully backward-compatible, no breaking changes

Sample App

• Queue tab now shows a LinearProgressIndicator with "Uploading... X%" during file upload
• Progress bar automatically hides once the upload completes and server-side processing begins

Changed Files

File	Change
sdk/.../queue/QueueTypes.kt	Added UploadProgressListener fun interface
sdk/.../queue/QueueClient.kt	Added ProgressRequestBody, onUploadProgress param on submit/submitAndPoll/submitAndObserve
sdk/.../DecartClient.kt	Trim API key on init
sample/.../MainActivity.kt	Upload progress bar UI in Queue tab
sdk/.../queue/QueueClientTest.kt	10 new tests for upload progress

Usage

// Simple lambda syntax (UploadProgressListener is a fun interface)
client.queue.submit(model, input) { bytesWritten, totalBytes ->
    if (totalBytes > 0) {
        val percent = (bytesWritten * 100 / totalBytes).toInt()
        Log.d("Upload", "Progress: $percent%")
    }
}

// With submitAndObserve (Flow)
client.queue.submitAndObserve(model, input) { bytesWritten, totalBytes ->
    updateProgressBar(bytesWritten.toFloat() / totalBytes)
}.collect { update ->
    when (update) {
        is QueueJobResult.InProgress -> showStatus(update.status)
        is QueueJobResult.Completed  -> saveVideo(update.data)
        is QueueJobResult.Failed     -> showError(update.error)
    }
}

Test plan

• Run ./gradlew sdk:test — all tests pass including 10 new upload progress tests
• Build and install sample app on emulator/device
• In sample app: Video tab → select video → submit → verify upload progress bar appears with percentage
• Verify progress bar disappears once status switches to PENDING/PROCESSING