backend: separated agent classes. frontend: chat message context menu (does nothing)

backend/database.py

@@ -29,7 +29,7 @@ class Agent(Base):
     id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
     user_id: Mapped[int] = mapped_column(ForeignKey("users.id"))
 
-    handle: Mapped[Optional[str]]
+    agentname: Mapped[Optional[str]]
     visibility: Mapped[int] = mapped_column(default=0)
     # Comma separated list of permission symbols
     permissions: Mapped[str] = mapped_column(default="")
@@ -86,4 +86,6 @@ class Message(Base):
     # Predefined set of message types, interpreted as 'text' when empty.
     kind: Mapped[str]
     content: Mapped[str]
+    # Tells whether this message continues in the chat after the session when it was sent.
+    persistent: Mapped[bool] = mapped_column(default=False)