fc3d: models — Source.consecutive_failures + ImportSettings scheduling knobs

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

backend/app/models/import_settings.py

@@ -38,3 +38,14 @@ class ImportSettings(Base):
     download_validate_files: Mapped[bool] = mapped_column(
         Boolean, nullable=False, default=True
     )
+
+    # FC-3d scheduling knobs
+    download_schedule_default_seconds: Mapped[int] = mapped_column(
+        Integer, nullable=False, default=28800
+    )
+    download_event_retention_days: Mapped[int] = mapped_column(
+        Integer, nullable=False, default=90
+    )
+    download_failure_warning_threshold: Mapped[int] = mapped_column(
+        Integer, nullable=False, default=5
+    )

backend/app/models/source.py

@@ -27,5 +27,6 @@ class Source(Base):
     last_checked_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
     last_error: Mapped[str | None] = mapped_column(Text, nullable=True)
     check_interval_override: Mapped[int | None] = mapped_column(Integer, nullable=True)
+    consecutive_failures: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
 
     artist = relationship("Artist", back_populates="sources")