DRY pass commit 1 (process #594). Consolidate the helpers + download plumbing
the Patreon and SubscribeStar adapters had duplicated (SubscribeStar was
importing patreon privates — wrong owner). New backend/app/services/
native_ingest_common.py is the neutral home for:
- make_session (was _load_session ×2), retry_after_seconds + 429 constants,
sanitize_segment, basename_from_url, post_dir_name, MediaOutcome /
PostRecordOutcome.
- BaseNativeDownloader: the shared streaming GET (transient-retry + Range-resume)
and validation/quarantine. Patreon + SubscribeStar downloaders now subclass it;
each keeps only what differs (Patreon's Mux/yt-dlp video branch + detail-fetch
enrichment; SubscribeStar nothing extra). Behavior preserved exactly; the
divergence-bug risk (a fix to one _fetch_to_file not reaching the other) is gone.
- Folds in #899 L2: a quarantine now log.warning's path+reason (was counted only).
post_dir_name merges both date handlers (accepts trailing-Z and pre-parsed ISO).
Tests repointed to the single source at every consumer (rule 93 / §8b parity):
patreon_client/downloader, subscribestar_native. Exception-trio consolidation +
base _failure_result (2/3) and the remaining ingest_core logging (3/3) follow.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
