feat(fc3b): migration 0011 — credential schema aligned with GS wire fields

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/app/models/credential.py

@@ -1,5 +1,8 @@
-"""Credential — encrypted blob (cookies/token/oauth) scoped per-platform,
+"""Credential — encrypted blob (cookies/token) scoped per-platform,
 not per-source. One Patreon credential serves every Patreon source.
+
+Schema aligned with GallerySubscriber's wire format (FC-3b) so the
+existing browser extension hits FC unmodified.
 """
 
 from datetime import datetime
@@ -15,10 +18,12 @@ class Credential(Base):
 
     id: Mapped[int] = mapped_column(Integer, primary_key=True)
     platform: Mapped[str] = mapped_column(String(64), nullable=False, unique=True)
-    kind: Mapped[str] = mapped_column(String(32), nullable=False)  # cookies|token|oauth
+    credential_type: Mapped[str] = mapped_column(String(32), nullable=False)  # cookies|token
     encrypted_blob: Mapped[bytes] = mapped_column(LargeBinary, nullable=False)
-    status: Mapped[str] = mapped_column(String(32), nullable=False, default="active")
     captured_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), nullable=False, server_default=func.now()
     )
     expires_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    last_verified: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), nullable=True
+    )