The documented import for `assert_output_satisfies` raises `ImportError`

## Bug Description

The import shown in `semantic.py`'s own module docstring fails.

## Root Cause

`src/conductor/ai/agents/testing/semantic.py:9` documents
`from conductor.ai.agents.testing import assert_output_satisfies`, but `testing/__init__.py`
never imports `semantic` and the name is absent from `__all__` (`__init__.py:61-97`).

## Steps to Reproduce

```
python -c "from conductor.ai.agents.testing import assert_output_satisfies"
# ImportError
```

## Expected Behavior

Either add the re-export or correct the docstring. The re-export looks like the intent, since
every other assertion in the package is exposed that way. Working import today is
`from conductor.ai.agents.testing.semantic import assert_output_satisfies`.

## Additional Notes

Verified against `origin/main` @ `c99e2cf9`. Found while reading the module; unrelated to the
tool-call and event defects filed separately.

Start with src/conductor/ai/agents/testing/semantic.py and src/conductor/ai/agents/testing/__init__.py, especially the documented import and the __all__ section at lines 61-97. Reproduce the failure with the Python command in the issue, then verify the chosen documentation or export behavior with the relevant testing package checks. Done means the documented import is consistent with the supported public API.

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