fix: allow users cancel backend download

[louis-jan]

Describe Your Changes

This PR allows users to cancel a backend download.

Recording.2025-09-24.175239.mp4

This pull request introduces improvements to the download management and error handling logic for backend downloads. The main changes enhance the user experience by ensuring that download cancellations and fallback mechanisms work more reliably and intuitively.

Download cancellation logic:

• Updated the download cancellation handler in DownloadManagement so that downloads with IDs starting with 'llamacpp' are cancelled using the @janhq/download-extension's cancelDownload method, while other downloads continue to use the existing serviceHub.models().abortDownload method. This ensures the correct cancellation mechanism is used for different types of downloads. [1] [2]

Backend download fallback and error handling:

• Improved error handling in the downloadBackend function to prevent unnecessary fallback attempts: now, if a GitHub download fails due to cancellation (specifically, if the error message is 'Error: Download cancelled'), it will not retry the download via the CDN. This avoids redundant operations and respects user-initiated cancellations.

Fixes Issues

• Closes bug: unable to cancel download on progress bar while backend is downloading #6132

Self Checklist

• Added relevant comments, esp in complex areas
• Updated docs (for bug fixes / features)
• Created issues for follow-up changes or refactoring needed

[ellipsis-dev]

Caution

Changes requested ❌

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[github-actions]

Barecheck - Code coverage report

Total: 30.03%

Your code coverage diff: -0.02% ▾

Uncovered files and lines

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web-app/src/containers/DownloadManegement.tsx

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