fix(cli,memory): catch typer.Exit in actor CLIs and align SQLChatMessageHistory kwarg

The `agents actor run` and `actor_run` Typer commands wrapped their main
try/except around `_resolve_config_files` with a bare `except
click.exceptions.Exit: raise` clause to let resolver-raised exits
propagate cleanly. Modern Typer re-exports `typer.Exit` from its vendored
click (`typer._click.exceptions.Exit`), which is NOT a subclass of
`click.exceptions.Exit`. So `_resolve_config_files`'s
`raise typer.Exit(code=2)` for unknown-actor / no-config-data / bad-blob
cases fell through to the generic `except Exception` clause, which
re-raised as `typer.Exit(code=3)` and replaced the targeted stderr
("not found in registry") with a generic "Unexpected error" message.
Behave scenarios at `actor_run_signature.feature:38` and `:56` and three
Robot integration scenarios verified the original exit-code/message
contract and failed. Catch `(typer.Exit, click.exceptions.Exit)` instead.

The five errored scenarios in `actor_run_signature_resolve_steps.py` and
`actor_run_signature_security_steps.py` had the same root cause from the
test side: `except (SystemExit, click.exceptions.Exit)` could not catch
the raised `typer.Exit`. Widen the tuple to include `typer.Exit`.

memory_service.py's `SQLChatMessageHistory(connection_string=...)` call
broke against langchain-community 0.4.2: the keyword was renamed
`connection` (which now accepts a URL string OR an Engine). Update the
call site and refresh the local `typings/langchain_community/...`
pyright stub to match the upstream signature so typecheck stays clean.

ISSUES CLOSED: #10921

typings/langchain_community/chat_message_histories/__init__.pyi

@@ -6,8 +6,12 @@ class SQLChatMessageHistory:
     def __init__(
         self,
         session_id: str,
-        connection_string: str,
-        table_name: str = "message_history",
+        table_name: str = "message_store",
+        session_id_field_name: str = "session_id",
+        custom_message_converter: Any | None = None,
+        connection: Any | None = None,
+        engine_args: dict[str, Any] | None = None,
+        async_mode: bool | None = None,
     ) -> None: ...
     @property
     def messages(self) -> list[Any]: ...