[fix] Enable adaptive downscale after client timeouts

[paul-fresquet]

Summary

• Downscale upload settings after consecutive client-side upload timeouts.
• Reduce parallelism before chunk size, then allow chunk size to go below 500 KB down to the 64 KB floor.
• Add unit coverage for timeout-driven downscale and minimum chunk size behavior.

Test plan

• dotnet test tests/ByteSync.Client.UnitTests/ByteSync.Client.UnitTests.csproj --filter AdaptiveUploadControllerTests
• dotnet test tests/ByteSync.Client.UnitTests/ByteSync.Client.UnitTests.csproj
• dotnet test tests/ByteSync.Client.IntegrationTests/ByteSync.Client.IntegrationTests.csproj

[Copilot]

Pull request overview

Enables adaptive downscaling of upload settings in response to repeated client-side upload timeouts, so uploads can recover by reducing parallelism first and then shrinking chunk size down to a 64 KB floor.

Changes:

• Track consecutive client timeouts and trigger a downscale after a fixed threshold.
• Refactor downscale logic into a shared helper and reuse it for both bandwidth-based and timeout-based downscales.
• Add/adjust unit tests to cover timeout-driven downscale behavior and minimum chunk size behavior.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/ByteSync.Client/Services/Communications/Transfers/Uploading/AdaptiveUploadController.cs	Adds consecutive-timeout tracking and reuses a unified Downscale(...) path for both timeout and slow-window triggers.
tests/ByteSync.Client.UnitTests/Services/Communications/Transfers/Uploading/AdaptiveUploadControllerTests.cs	Adds unit coverage for timeout-driven downscale (parallelism-first and chunk-size floor).

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[sonarqubecloud]

Quality Gate passed

Issues
8 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud