A local ExternalImageURL was resolved through the external step and labelled
external, so placeBytes copied it into the content-addressed store and dropped its
path/mtime — replacing the file never tripped the staleness check. Classify local
references as file-backed (resolved in place, even on the request path) and keep
store-backed behaviour only for http(s) URLs.
decodeTile ran image.Decode on every sampled album's resolved bytes
before processItem's maxImageBytes/maxImagePixels guards applied,
letting an oversized or decompression-bomb tile fully decode
unbounded. Enforce both caps inside decodeTile itself.
The playlist ExternalImageURL step used sources.go's fromURL, which maps any
non-200 to a generic error, so a stale URL returning 404/410 was classified
transient: infinite backoff plus it counted toward the circuit breaker,
blocking valid external work. Add a local fetch in resolve.go that maps
404/410 to model.ErrNotFound (definitive) while keeping other non-200s
transient. sources.go is left untouched.
With CoverArtPriority="external,cover.jpg", a transient external failure
followed by a folder hit dropped the external error: the worker recorded
found and deleted the queue row, so the configured higher-priority external
art was never retried. Carry extError onto the fallback resolution and add
an outcomeFoundStale that persists+serves the art but reschedules via
MarkFailed, giving the external source another chance. When external later
answers definitively-not-found, the hit is not stale and the row is deleted.
A playlist ExternalImageURL pointing at a local file that fails to open was
routed through extError, causing failed/48h-retry loops that burn a rate
limiter token forever instead of falling through to the generated grid.
resolvePlaylist only built the generated grid, dropping the uploaded-image, sidecar and ExternalImageURL sources the old reader_playlist.go chain serves. Port the full chain before the grid fallback: uploaded (upload), sidecar (folder), and ExternalImageURL routed through extGate with the same extError semantics as the other external steps. Also rewires the artist external step onto ArtistImageResult.
