fix: the membership status vocabulary moves beside Membership, so the Patreon client never imports the roster

240f11c made PatreonClient._membership import has_paid_access from membership_roster. test_gated_reason::test_no_fetch_path_can_read_the_roster failed on it, correctly: native_ingest_common is a fetch root, patreon_client is reachable from it, and no fetch path may be able to reach the roster. The roster is allowed to explain a skip, never to cause one.

MEMBERSHIP_STATUS and has_paid_access are pure platform knowledge with no database behind them. They move to native_ingest_common, next to the Membership type they interpret (the same move C7 made for Membership itself). membership_roster, membership_reconcile, patreon_client and the tests import them from there. There is no re-export from membership_roster.

The guard is unchanged. The lapsed-orphan skip from 240f11c stays as it was.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SHQB1YukL3VyvMK8rcbmV9

backend/app/services/subscribestar_client.py

@@ -316,7 +316,7 @@ _ROSTER_URL = f"{_ROSTER_BASE}/subscriptions"
 # `data-identifier`, the one vocabulary that names a state: the table class
 # inside the cancelled card says `for-unsubscribed_users`, a different word for
 # the same list (note #3989, CORRECTION 1). The identifier is stored verbatim as
-# Membership.status and mapped in membership_roster.MEMBERSHIP_STATUS.
+# Membership.status and mapped in native_ingest_common.MEMBERSHIP_STATUS.
 _ROSTER_ACTIVE = "active_subscriptions"
 _ROSTER_CANCELLED = "cancelled_subscriptions"