Rename models.py to types.py across all environments

[Copilot]

Problem

The file name models.py in environment directories was causing confusion, as readers typically expect "models" to refer to machine learning models (neural networks, transformers, etc.). However, these files actually contain data type definitions - dataclasses for Action, Observation, and State types used by each environment.

Solution

Renamed all models.py files to types.py across all environments to better reflect their actual purpose. The name "types" clearly indicates these files contain type definitions and is understood by both AI/ML and infrastructure engineers.

Changes

Files Renamed

• src/envs/atari_env/models.py → types.py
• src/envs/coding_env/models.py → types.py
• src/envs/echo_env/models.py → types.py
• src/envs/chat_env/models.py → types.py
• src/envs/openspiel_env/models.py → types.py

Updated References

• All Python imports changed from .models to .types (34 files total)
• Documentation updated in README.md, src/envs/README.md, and environment-specific READMEs
• Docstring examples in core files updated
• File docstrings changed from "Data models" to "Data types" for consistency

Why "types"?

The name types.py was chosen because:

• ✅ Clearly indicates the file contains type definitions
• ✅ Familiar to both AI/ML and infrastructure engineers
• ✅ Aligns with existing patterns in the codebase (core/types.py)
• ✅ Avoids confusion with ML models (neural networks)

Testing

• ✅ Verified all imports work correctly across all 5 environments
• ✅ Confirmed type definitions can be instantiated without errors
• ✅ No breaking changes to existing functionality
• ✅ Security scan passed with 0 vulnerabilities

Example Usage (unchanged)

The API remains exactly the same for users:

from envs.echo_env import EchoAction, EchoEnv

client = EchoEnv.from_docker_image("echo-env:latest")
result = client.step(EchoAction(message="Hello!"))

Users import from the environment package (envs.echo_env), so the internal file rename is transparent to them.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Rename .model() in the spec</issue_title>
<issue_description>As discussed, the reader will expect something very different to be in our model.py files :D Let's rename to something better. Claude can do this task, just creating an issue so we decide what to name it.</issue_description>

<agent_instructions>Use a name that both AI people and infra people will understand.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

Fixes #42

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[pankit-eng]

lets avoid using types.py in general because of conflicting imports that might happen with python std types. Like: cannot import name 'MappingProxyType' from partially initialized module