- JenkinsClient: streaming download API (DownloadTask/DownloadProgressEvent)
with cancel support via subscription teardown
- ArtifactStagingService: temp-dir staging, partial file cleanup on error/cancel,
APK existence/extension/size verification, and post-install cleanup hook
- BuildsPage: _InstallCta upgraded to StatefulWidget with idle→downloading→
verified/failed/cancelled state machine; LinearProgressIndicator and cancel button
Closes download-progress, temp-download, artifact-verify tasks.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
