icon/image/logo/cover_image are now MinIO object keys, not URLs -- every
serializer with one of these fields now returns a <field>_url sibling
that's an already-absolute, freshly presigned URL. Added those fields to
every affected type (StoreCategory, StoreListItem, ProductCategory,
ProductListItem) and switched every <img> call site to use the _url field
directly.
Deleted resolveMediaUrl/resolveClientMediaUrl and the
NEXT_PUBLIC_WINOFY_MEDIA_ORIGIN env var -- they existed only to turn
relative paths under the Winofy origin into absolute URLs, which no longer
applies now that media lives on a different host (MinIO) and comes back
pre-resolved.
Also fixes cart-item-row.tsx's product thumbnail, which had been commented
out (broken under the old relative-path assumption).
Restored image_url as a required non-optional field per the doc rather
than treating it as possibly-missing, since every serializer covered by
this migration always includes it (null when no image, not omitted).
