bug: propagate_types_to_choice=[] ignored — tool attachments still pushed to choice

[VinShurik]

QuickApps version

latest

What steps will reproduce the bug?

1. Configure a dial-mcp tool pointing at a deployment that returns attachments, e.g.:

{
    "type": "dial-mcp",
    "deployment_id": "toolsets/public/document_vision__1.0.0",
    "attachment": {
        "propagate_types_to_choice": []
    }
}

2. Trigger a tool call that returns an attachment whose MIME type is not in the (empty) allow-list.
3. Observe the chat response / choice.

What is the expected behavior?

With propagate_types_to_choice set to [], no tool attachments should be pushed to the choice.
matches_type(type, []) in src/quickapp/common/utils.py returns False for every type, so
StagedBaseTool._run_in_stage_report_success (src/quickapp/common/staged_base_tool.py:316)
should not append any attachment to result.propagate_to_choice.

What do you see instead?

Tool message attachments are still pushed to the choice — the flag has no effect.

Additional information

The direct tool_call_result.propagate_to_choice path in staged_base_tool.py does appear to
honor the empty list correctly. The leak looks like it comes from a second path: attachments kept
in context for the orchestrator model (keep_in_context_types) get echoed back by the LLM in its
own assistant-message stream, and ChoiceUiSink._add_attachments
(src/quickapp/common/chat_completion_stream/choice_ui_stream_sink.py) currently adds every
attachment from that stream to the choice unconditionally, with no awareness of the tool's
propagate_types_to_choice config. This second path isn't gated by the attachment config at all.