feat: RDG session flap rule, qwinsta/logoff queue and dashboard UI (0.9.13)

Detect 302→303 within 1–10s, Problem with 30s dedup, rdg_flap flag.
Agent command poll API, admin qwinsta/logoff from Overview. Migration 016.

backend/app/models/__init__.py

@@ -1,3 +1,4 @@
+from app.models.agent_command import AgentCommand
 from app.models.api_key import ApiKey
 from app.models.event import Event
 from app.models.host import Host
@@ -16,6 +17,7 @@ from app.models.mobile_refresh_token import MobileRefreshToken
 
 __all__ = [
     "ApiKey",
+    "AgentCommand",
     "Event",
     "Host",
     "NotificationChannel",

backend/app/models/agent_command.py

@@ -0,0 +1,27 @@
+from datetime import datetime
+
+from sqlalchemy import DateTime, ForeignKey, String, Text, func
+from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.database import Base
+
+
+class AgentCommand(Base):
+    __tablename__ = "agent_commands"
+
+    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
+    command_uuid: Mapped[str] = mapped_column(String(36), unique=True, index=True)
+    host_id: Mapped[int] = mapped_column(ForeignKey("hosts.id", ondelete="CASCADE"), index=True)
+    event_id: Mapped[int | None] = mapped_column(ForeignKey("events.id", ondelete="SET NULL"), nullable=True)
+    command_type: Mapped[str] = mapped_column(String(32))
+    params: Mapped[dict | None] = mapped_column(JSONB, default=dict)
+    status: Mapped[str] = mapped_column(String(16), default="pending", index=True)
+    result_stdout: Mapped[str | None] = mapped_column(Text)
+    result_stderr: Mapped[str | None] = mapped_column(Text)
+    requested_by: Mapped[str | None] = mapped_column(String(128))
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
+    completed_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
+
+    host: Mapped["Host"] = relationship(back_populates="agent_commands")
+    event: Mapped["Event | None"] = relationship()

backend/app/models/host.py

@@ -28,3 +28,4 @@ class Host(Base):
     created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
 
     events: Mapped[list["Event"]] = relationship(back_populates="host")
+    agent_commands: Mapped[list["AgentCommand"]] = relationship(back_populates="host")