* fix(subagents): build the chat model off the event loop
`SubagentExecutor._create_agent` is awaited from `_aexecute` on the shared
event loop, and it constructed the chat model inline. Provider construction can
read local credentials -- the Codex provider loads the Codex CLI `auth.json`
while it is built -- so every delegated task did synchronous file IO on the loop
before its first model call, which stalls every concurrent turn sharing that
loop.
Build the model through `run_assembly`, the dedicated assembly pool the other
provider-construction sites already use, and leave the rest of the middleware
and graph assembly where it is. The helper preserves request context, and a
cancelled construction still never starts an inference.
`tests/blocking_io/test_subagent_model_offloop.py` drives the real
`_create_agent` with a real `CodexChatModel` under the strict Blockbuster gate:
on `main` the credential load fails with `BlockingError(os.stat)`, and reverting
the `run_assembly` call reproduces the same failure.
* docs(subagents): name the isolated subagent loop in the off-loop notes
The blocked loop is the persistent isolated subagent loop every concurrent
delegated task shares, not the Gateway request loop; say so in the boundary
audit, the regression docstring, and the assertion message.
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Co-authored-by: Totoro <msy626836554@gmail.com>
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