* Fix picture-loader cache formats, redirects and offline queue handling
* Format picture-loader changes using project style
* Address review: name decoded image fields, test cancelled requests
Use designated initializers for DecodedImage so a field reorder cannot
silently swap the image and its error string.
Extract the cancelled-request sweep shared by the dispatcher and the
single-request path into takeCancelledRequests(), and cover it: one status
retirement per vanished work item, in queue order, with live entries kept.
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Co-authored-by: Lukas Brübach <44814898+BruebachL@users.noreply.github.com>
