fix: show partial download progress on initial dashboard load - #1706

Summary

• Dashboard now shows partial download progress for models that were partially downloaded in a previous session, instead of showing 0%
• Both getModelDownloadStatus() and getInstanceDownloadStatus() now handle DownloadPending entries that carry non-zero downloaded/total bytes

Fixes #1042

Root cause

When exo restarts with partially downloaded models, the DownloadCoordinator emits DownloadPending events (because downloaded_this_session is 0, even though real bytes exist on disk). The main page dashboard only checked for DownloadOngoing entries, so these partially downloaded models showed as 0%.

The dedicated /downloads page already handled this correctly — it renders DownloadPending entries with a progress bar when downloaded > 0. This fix brings the same behavior to the main page.

Changes

For both getModelDownloadStatus() and getInstanceDownloadStatus() in +page.svelte:

• Accept DownloadPending in addition to DownloadOngoing
• For DownloadPending entries with downloaded > 0 or total > 0, synthesize a DownloadProgress object from the top-level fields (with speed: 0 and etaMs: 0 since no active download is in progress)
• Skip DownloadPending entries where both downloaded and total are 0 (truly pending, not yet started)

Test plan

• Partially download a model, quit exo, relaunch — dashboard should show partial progress instead of 0%
• Fully downloaded models still show as complete
• Active downloads still show real-time progress with speed/ETA
• Models never downloaded show as not started (not falsely showing progress)
• Dashboard builds without errors (cd dashboard && npm run build)