Manifest served from blob: URL — start_url, scope and icon src rejected; app fails Chrome installability criteria

[MBobie]

Summary

The web app manifest is served from a blob: URL
(blob:https://baobab.deeplearningindaba.com/c1a98e17-…). Relative URLs
cannot resolve against a blob origin, so start_url, scope and the icon
src entries are rejected. Chrome's Application → Manifest panel reports the
app as failing installability criteria.

Manual "Install page as app" still works, since Chrome allows installing any
page as a shortcut, but the automatic install prompt never fires and the
declared start_url and scope are discarded.

Actual — DevTools → Application → Manifest

Errors and warnings:

• property 'start_url' ignored, URL is invalid
• property 'scope' ignored, URL is invalid
• property 'src' ignored, URL is invalid (×2)
• Richer PWA Install UI unavailable on desktop and mobile (no screenshots
  with form_factor declared)
• Declaring an icon with 'purpose' of 'any maskable' is discouraged (×2)

Installability:

• Manifest 'start_url' is not valid
• Manifest does not contain a suitable icon — PNG, SVG or WebP of at least
  144px required, 'sizes' must be set, 'purpose' if set must include 'any'

Note: the panel also reports no id field, so start_url is used as the
computed App ID. With start_url invalid, app identity is resting on a
rejected value.