DRY pass commit 2. The two adapters re-implemented the same auth→drift→429→404
→http→network mapping in _failure_result; only the exception classes + drift
phrasing differed (divergence-bug risk: a new error_type handled in one and not
the other).
- native_ingest_common gains NativeIngestError / NativeAuthError / NativeDriftError
(status_code + retry_after on the base). Patreon{API,Auth,Drift}Error and
SubscribeStar{API,Auth,Drift}Error now subclass them via multiple inheritance,
keeping their isinstance-distinct platform names.
- Ingester._failure_result (base) does the whole mapping via the shared
NativeAuthError/NativeDriftError taxonomy + status_code; a new platform gets it
free. New drift_label kwarg supplies the per-platform API_DRIFT phrasing
("Patreon API" / "SubscribeStar markup"), preserving the existing message
(test asserts "Patreon API changed").
- Both adapters drop their near-identical _failure_result overrides and their now
-unused DownloadResult/ErrorType/*Auth/*Drift imports.
Verified at every consumer (rule 93/§8b): test_patreon_ingester (auth/drift/429/
404/network) and test_subscribestar_native (_failure_result mapping) both exercise
the base method now. Remaining: ingest_core L1/L3 logging (3/3).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
bvandeusen
ebe6ab9741