Add wide (1024x515) and narrow (390x844) screenshots to the web app
manifest so Chrome displays the richer install UI with a preview on
both desktop and mobile. Register screenshots directory in
web_accessible_resources so Chrome can fetch the images from the
extension origin.
Replace all extension icons (16, 32, 48, 128, 192, 512) with versions
derived from the new 512x512 brand icon for consistency. Add 192x192
and 512x512 entries to manifest.webmanifest — Chrome requires both
sizes to show the "Install page as app" option in the browser menu.
Mark the 512px icon as maskable for OS launcher compatibility.
Add manifest.webmanifest to the dashboard so Chrome can install it as
a standalone app via the browser menu. Register the manifest in
web_accessible_resources and link it from dashboard.html. Add a
dedicated PWA install section to docs/INSTALLATION.md covering install
steps, uninstall, and the requirement that the extension remains
installed.