added scheduled scan feature

app/models/scheduled_scan.py

@@ -0,0 +1,42 @@
+import uuid
+from datetime import datetime, timezone
+
+from sqlalchemy import Boolean, DateTime, ForeignKey, Integer, String
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.database import Base
+
+
+class ScheduledScan(Base):
+    """
+    Represents a user-configured recurring scan for a URL.
+
+    schedule  : "daily" or "weekly" — controls how the APScheduler job
+                triggers re-scans.
+    last_run_at : timestamp of the last completed scheduled scan.
+    last_score  : security score from the last run, used to detect regressions.
+                  If the new score is lower, a webhook is fired.
+    is_active   : soft toggle — paused scans stay in the DB but are skipped
+                  by the scheduler.
+    """
+
+    __tablename__ = "scheduled_scans"
+
+    id: Mapped[str] = mapped_column(
+        String(36), primary_key=True, default=lambda: str(uuid.uuid4())
+    )
+    user_id: Mapped[str] = mapped_column(
+        String(36), ForeignKey("users.id", ondelete="CASCADE"), index=True
+    )
+    url: Mapped[str] = mapped_column(String(2048))
+    schedule: Mapped[str] = mapped_column(String(10), default="daily")
+    is_active: Mapped[bool] = mapped_column(Boolean, default=True)
+    last_run_at: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), nullable=True, default=None
+    )
+    last_score: Mapped[int | None] = mapped_column(Integer, nullable=True, default=None)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
+    )
+
+    user = relationship("User", back_populates="scheduled_scans")