[codex] Feedback fixture: no iterations completed

[alonso-ih]

Fixture PR for testing feedback behavior on a lab submission with no iterations completed.

Scenario:

• No required iteration is implemented.
• src/index.js only contains a neutral student note so the branch has a diff and can be reviewed as a PR.
• Iteration 1, Iteration 2, Iteration 3, and bonus work remain as starter code.

Validation:

• Reviewed the diff to confirm no functional implementation was added.
• No local test suite is available in this repository because it does not include package.json.