The Discord/Telegram /model slash command listed providers synchronously
on the gateway's async event loop. list_picker_providers /
list_authenticated_providers are blocking and can fall through to a
synchronous urllib HTTP fetch when the on-disk provider cache is stale,
freezing the loop for 120-150s -> "application did not respond" and
delayed agent starts.
Port #41304's asyncio.to_thread offload to the current handler location.
The handler moved from gateway/run.py to gateway/slash_commands.py
(_handle_model_command); wrap BOTH blocking call sites so the whole bug
class is covered:
- picker path -> list_picker_providers
- text-fallback path -> list_authenticated_providers
asyncio.to_thread is already idiomatic in this module (and asyncio is
imported), so the loop now stays responsive while the (possibly
network-bound) listing runs on a worker thread.
Adds tests/gateway/test_model_command_async_offload.py asserting the
offload contract at the real handler seam for both paths (mutation-
survivable: reverting either to_thread wrap fails the matching test).
Co-authored-by: kshitijk4poor <82637225+kshitijk4poor@users.noreply.github.com>
