Closes#1014
- llm.ToolOutput(output='...', attachments=[...]) for tools to return attachments
- New table: `tool_results_attachments`
- Table is populated when tools return attachments
- llm --tools-debug shows attachments returned by tools
- llm logs shows attachments returned by tools
* Sync models can now call async tools, refs #987
* Test for async tool functions in sync context, refs #987
* Test for asyncio tools, plus test that they run in parallel
* Docs for async tool usage
