Incorrect Order Handling in expected_stdout_lines Matching Logic

Given an step:

```text
name: Run Chaining Pattern workflow
match_order: none
output_match_mode: substring
expected_stdout_lines:
- 'Activity returned: 2'
- 'Activity returned: 9'
- 'Activity returned: 21'
- 'Activity returned: 17'
- 'Workflow finished with result: 60'
```

The verification executes in the `expected_stdout_lines` in [order](https://github.com/dapr/mechanical-markdown/blob/2ce1c907d05e987e4e64472256267a5caeef51fe/mechanical_markdown/step.py#L144), then the first line to be verified is `Activity returned: 2`.

If the output shows first `Activity returned: 21` the first line (`Activity returned: 2`) will be matched and the following line will be [removed](https://github.com/dapr/mechanical-markdown/blob/2ce1c907d05e987e4e64472256267a5caeef51fe/mechanical_markdown/step.py#L157).

Start in mechanical_markdown/step.py at the verification logic around lines 144 and 157, using the linked workflow example to reproduce the substring collision. Check how match_order: none processes expected_stdout_lines and how matched output lines are removed. Done means a longer output such as “Activity returned: 21” is not incorrectly consumed by the expected “Activity returned: 2” entry.

Written by the indexing model from the issue text.