The manifest's largest, maskable icon (ms-icon-310x310) was transparent,
so installing the PWA produced a transparent app icon. Generate opaque
192/512 "any" + maskable icons from favicon-bg.png (solid #524B6B
background, maskable variants padded into the inner 80% safe zone) and
point the manifest at them instead of the transparent ms-icon entry.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
