feat: SAC 0.7.0 display_name columns and event severity overrides

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/models/event_severity_override.py

@@ -0,0 +1,19 @@
+from datetime import datetime
+
+from sqlalchemy import DateTime, String, func
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.database import Base
+
+
+class EventSeverityOverride(Base):
+    __tablename__ = "event_severity_overrides"
+
+    event_type: Mapped[str] = mapped_column(String(128), primary_key=True)
+    severity: Mapped[str] = mapped_column(String(16), nullable=False)
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+        onupdate=func.now(),
+        nullable=False,
+    )