type-clean the test files so make quality (mypy roboco/ tests/) is green:
- Any-typed locals for the two TypeError-asserting scoping tests (bypass
the required-arg check without getattr/ruff B009)
- Any-typed view for the shutdown-drain _drain_bg_tasks override (bypass
mypy method-assign without setattr/ruff B010)
- cast("uuid.UUID", ...) / cast("UUID", ...) for SQLAlchemy UUID[Any]
returns (TC006-quoted), config=None for AgentInstance stubs, None-narrowed
await_args, Iterator return on a yielding fixture, UUID annotation on the
_task helper. No type:ignore / noqa.