agent: test the accuracy of agent after incorporating linter result to the file_editor

[xingyaoww]

What problem or use case are you trying to solve?

Currently, our str_replace_editor (https://github.com/All-Hands-AI/OpenHands/tree/main/openhands/runtime/plugins/agent_skills/file_editor/impl.py) performs edit, but doesn't really do any linter checks.

Describe the UX of the solution you'd like

Every time an edit is performed inside file_editor, the linter will be run and print out linter outputs to STDOUT.

Do you have thoughts on the technical implementation?

• See tests/unit/linters/test_lint_diff.py about how to use the current OpenHands Linter
• Change the EditTool in openhands/runtime/plugins/agent_skills/file_editor/impl.py by importing, and initializing Linter. Then run the linter whenever an edit is performed, and concatenate linter error results if there's a linter error.