[murainah]

What GitHub issue does this PR apply to?

Resolves #826

What changed and why?

validatelanginfofiles crashed with AttributeError: 'list' object has no attribute 'items' when a language file was valid JSON but its concepts value was not an object (for example "concepts": []), instead of reporting a validation error.

check_concepts now checks that concepts is a dict. If it isn't, it reports an error in the validator's usual style and returns, so the command keeps going and counts the error:

[Error] `langs/python/3/data_types.json` has a `concepts` section that is not an object

Following AGENTS.md (TDD), I added the regression test first (test_validatelanginfofiles_reports_non_object_concepts in web/tests/test_commands.py). It runs the real validate_language_file path on a temporary file. It failed with the AttributeError before the fix and passes after it. Valid files behave exactly as before.

Checks I ran locally:

• python manage.py test: 130 tests pass
• python manage.py validatemetainfofile and python manage.py validatelanginfofiles: no errors on the real data
• isort --profile black --check-only is clean on the two files I changed

AI bots used in the process of making this PR

I used Claude (Anthropic's AI assistant) to help me find this project, to draft the issue text (#826), and to help write the regression test and the fix. I reproduced the crash myself in the Django shell, ran the new test to confirm it failed first, applied the change, and ran the full test suite, both validators and isort. I read the code I'm submitting and understand it.

Checklist

• I claimed any associated issue(s) and they are not someone else's
• I have looked at documentation to ensure I made any revisions correctly
• I tested my changes locally to ensure they work
• For language files, I have validated the edited files are valid JSON and data shows up correctly
• For website code edits, I have added or edited any appropriate unit tests for my changes
• If I used artificial intelligence (AI), I have reviewed the suggested changes and ensured they work correctly

Any additional comments or things to be aware of while reviewing?

• I opened validatelanginfofiles crashes with AttributeError when "concepts" is not a JSON object #826 myself and asked to be assigned in the issue. I haven't had a reply yet, so I'm opening this PR to keep to my deadline, and I'm happy to adjust anything.
• This PR only covers a non-object concepts section. The same kind of crash can happen for the other non-object cases listed in validatelanginfofiles crashes with AttributeError when "concepts" is not a JSON object #826 (a non-object top-level value, meta, or an individual concept entry). I left them out to keep the change small, and I can do them in a follow-up PR if you'd like.
• I didn't touch any language data files, so the "language files" checkbox doesn't apply.