feat: require gate reset before post-stop reentry

app/models/paper_trade.py

@@ -36,3 +36,13 @@ class PaperTrade(Base):
     closed_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
     # How the trade was closed: "time" | "trailing" | "stop" | "target" | "manual".
     close_reason: Mapped[str | None] = mapped_column(String(10), nullable=True)
+    # A trade stopped at its initial stop starts a re-entry gate-reset episode.
+    # The daily full-universe scanner records both state transitions: the first
+    # failed gate observation and a later fresh qualification. Re-entry remains
+    # non-actionable until both timestamps exist.
+    reentry_gate_failed_at: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), nullable=True
+    )
+    reentry_gate_requalified_at: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), nullable=True
+    )