Render a post body faithfully by serving our stored copies of inline
images instead of hotlinking the public CDN. The join key is the CDN
filehash (32-hex MD5) shared between a body <img src> and the media URL
we downloaded (the same identity extract_media dedups by):
- utils.paths.filehash_from_url — one source of truth for the extractor;
patreon_client._filehash now delegates so capture- and render-time
hashing cannot drift.
- ImageRecord gains source_url (provenance) + source_filehash (indexed
match key); migration 0051.
- the per-media sidecar carries the file's source_url; the importer
persists it (NULL-only) on the ImageRecord via _apply_sidecar.
- post_feed_service.get_post remaps body <img src> -> /images/<path> for
every inline image whose filehash maps to a stored image of THIS
artist; unmatched / pre-Phase-2 images keep hotlinking.
Pre-existing on-disk images have no filehash yet, so they fall back to
hotlinking until re-downloaded; localization is forward-looking.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
