fix: ruff lint + format fixes in tests, ESLint fixes in frontend

backend/app/models/copilot.py

@@ -16,6 +16,7 @@ from app.database import Base
 
 class CopilotRole(str, enum.Enum):
     """Roles for chat messages."""
+
     user = "user"
     assistant = "assistant"
 
@@ -37,10 +38,14 @@ class CopilotSession(Base):
         index=True,
     )
     title: Mapped[str] = mapped_column(
-        String(255), nullable=False, default="Neue Konversation",
+        String(255),
+        nullable=False,
+        default="Neue Konversation",
     )
     created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), nullable=False, server_default=func.now(),
+        DateTime(timezone=True),
+        nullable=False,
+        server_default=func.now(),
     )
     updated_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True),
@@ -57,7 +62,9 @@ class CopilotSession(Base):
     )
 
     def __repr__(self) -> str:
-        return f"<CopilotSession id={self.id} user_id={self.user_id} title={self.title}>"
+        return (
+            f"<CopilotSession id={self.id} user_id={self.user_id} title={self.title}>"
+        )
 
     def to_dict(self) -> dict:
         """Serialize session for API responses."""
@@ -99,16 +106,22 @@ class CopilotChat(Base):
     )
     content: Mapped[str] = mapped_column(Text, nullable=False)
     actions: Mapped[list | None] = mapped_column(
-        JSONB, nullable=True, default=None,
+        JSONB,
+        nullable=True,
+        default=None,
     )
     created_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), nullable=False, server_default=func.now(),
+        DateTime(timezone=True),
+        nullable=False,
+        server_default=func.now(),
     )
 
     session: Mapped["CopilotSession"] = relationship(back_populates="messages")
 
     def __repr__(self) -> str:
-        return f"<CopilotChat id={self.id} role={self.role} session_id={self.session_id}>"
+        return (
+            f"<CopilotChat id={self.id} role={self.role} session_id={self.session_id}>"
+        )
 
     def to_dict(self) -> dict:
         """Serialize chat message for API responses."""
@@ -116,7 +129,9 @@ class CopilotChat(Base):
             "id": str(self.id),
             "session_id": str(self.session_id),
             "user_id": str(self.user_id),
-            "role": self.role.value if isinstance(self.role, CopilotRole) else self.role,
+            "role": self.role.value
+            if isinstance(self.role, CopilotRole)
+            else self.role,
             "content": self.content,
             "actions": self.actions,
             "created_at": self.created_at.isoformat() if self.created_at else None,