Add OpenModelDB (openmodeldb.info) as a metadata and download source for
the existing upscaler model type.
Metadata:
- New OpenModelDBClient: fetches the site's bulk JSON dumps, caches them
on disk (24h TTL + ETag revalidation), and builds a local sha256 index
- New OpenModelDBModelMetadataProvider adapts catalogue entries to the
CivitAI-shaped version dict contract; registered in the fallback chain
behind the enable_openmodeldb_api setting (default on), gated to the
upscaler sub-type so other model types never trigger the dump download
- Persisted provenance uses metadata_source "openmodeldb" plus a nested
openmodeldb block (page URL, architecture, scale, license)
Images: paired-image LR/SR URLs are ephemeral imgdiff.net sessions, so
displayable images come from the site-hosted auto-generated thumbnails
(model-level cover leads images[], per-image thumbs for the rest); the
original comparison URL is kept in meta.comparisonUrl.
Downloads:
- New OpenModelDBSource (flat model ids, omdb: group prefix) with
resource filename derivation that recovers names hidden mid-path
(mediafire) or synthesizes {id}.{type} for folder links
- HTML-gateway mirrors (mediafire/mega/drive) are rejected with a clear
manual-download hint instead of silently saving an HTML page as .pth
- ModelSource base gains is_valid_source_id / default_subdir_parts /
resolve_download_url hooks so flat-id sources need no platform branches
UI: "View on OpenModelDB" link in the model modal (downloaded and
hash-enriched models), settings toggle next to the CivArchive one.
