Leftover boilerplate: dev.py, preview.py, healthcheck and return annotation are all broken

[peterbjohnson]

Four small defects left over from the template. None affect the deployed eval path, but each misleads anyone working on the repo.

1. dev.py fails immediately. The documented command in the README crashes:

python -m evaluation_function.dev "<response>" "<answer>"
AttributeError: 'dict' object has no attribute 'to_dict'

evaluation_function() returns a plain dict, so result.to_dict() is invalid. The arguments are also passed in the wrong order: the docstring says <answer> <response> and the call site passes evaluation_function(answer, response, ...), while the real signature is (response, answer, params).

2. healthcheck reports an error inside the container.

FileNotFoundError: /app/data/longMIDIsequence.json

evaluation_test.py opens the bulk-case fixture at import time, but the Dockerfile copies only evaluation_function/. Either copy data/ into the image or load the fixture lazily / skip when absent.

3. preview.py is still the boilerplate sympy preview. It echoes the notes back under a sympy key, which is meaningless for MIDI. Either implement something useful (e.g. note count and duration) or remove the preview registration.

4. Wrong return annotation. evaluation_function is annotated -> Result but returns a dict. Same for the unused Result/Params imports it implies.