planemo run --no_wait crashes with UnboundLocalError for tools

> _Posted by Claude (AI assistant) on behalf of @jmchilton — they did not author this text personally._

`planemo run --no_wait ` submits the job and then crashes with an `UnboundLocalError`. The workflow path is fine; this is tool-only, and it has never worked.

## Cause

In `planemo/galaxy/activity.py::_execute`, `run_response = None` is set at line 266. The tool branch (line 274) assigns `response_kwds` only inside `if not kwds.get("no_wait"):` (lines 289-307) and never assigns `run_response`. So with `--no_wait` the function falls through to line 338 `if not run_response:` and then line 347:

```
File "planemo/galaxy/activity.py", line 347, in _execute
**response_kwds,
^^^^^^^^^^^^^
UnboundLocalError: cannot access local variable 'response_kwds' where it is not associated with a value
```

The workflow branch assigns `run_response` via `invocation_to_run_response`, so it never reaches that line.

## Reachable from the CLI

`--no_wait` comes from `no_wait_option()` (`planemo/options.py:1826`) via `engine_options()` (`options.py:1727`), applied by `cmd_run.py:37` and `cmd_test.py`. Nothing in `cmd_run.py` or `planemo/engine/` guards it by runnable type, and `GalaxyEngine.handled_runnable_types` includes `galaxy_tool`/`cwl_tool`.

End-to-end, with only the Galaxy server mocked:

```
$ planemo run --no_wait project_templates/demo/cat.xml job.yml
Failed to execute Galaxy activity, throwing ErrorRunResponse
Run failed [Run failed with message [cannot access local variable 'response_kwds' where it is not associated with a value]]
```

Exit code 1. Same for the external engine (`--galaxy_url ... --no_wait `) and `planemo test --no_wait `.

## Provenance

Introduced by 15b4126d ("add --no_wait flag to run subcommand", 2021-04-27), which wrapped the tool-branch body in `if not kwds.get('no_wait'):` and pulled `response_kwds` under the guard - while the workflow branch in the same commit assigns it unconditionally. The tool path has been broken since the flag was added. The only test exercising `--no_wait` (`tests/test_external_galaxy_commands.py:95`) uses a workflow.

## Impact

The tool job **is** submitted to Galaxy before the crash, so the user sees "Run failed" and a non-zero exit for a job that is in fact running - bad for scripted use.

## Suggested fix

Mirror how the workflow path degrades under `no_wait`. Add an `else` to the guard at `activity.py:289`:

```python
else:
response_kwds = {
"job_info": None,
"api_run_response": tool_run_response,
}
```

`GalaxyToolRunResponse.__init__` already takes `job_info`, and `GalaxyBaseRunResponse` defaults `successful=True`, so `cmd_run` then prints "Run successfully executed - exiting without waiting for results." as it does for workflows. The harness in `tests/test_galaxy_activity.py` is a line away from covering this.

## Adjacent bug found while investigating

`cmd_run.py:84` calls `run_result.structured_data()` on the `ErrorRunResponse`, and `planemo/runnable.py:647` does `assert isinstance(self, SuccessfulRunResponse)`. So **any** failed `planemo run` ends in an uncaught `AssertionError` after the "Run failed" message instead of exiting cleanly. That is independent of `--no_wait` and probably deserves its own fix.

Start in planemo/galaxy/activity.py::_execute and compare the tool and workflow handling of --no_wait. Use the harness in tests/test_galaxy_activity.py, along with tests/test_external_galaxy_commands.py, to verify that a tool submission returns successfully without waiting and that the CLI exits cleanly.

Written by the indexing model from the issue text.