[Frontend][108dev] Essays history shows non-submission resources as if they were evaluations

[Cataldir]

Summary

On the Essays page, Submission History includes non-submission resources (rubrics/reference criteria) for the selected essay, causing confusing rows with:

• "Evaluation not available"
• labels that look like student submissions but are actually criteria content

User impact

• Teachers/students cannot reliably identify real historical essay evaluations.
• UI appears misconfigured even when backend connectivity is healthy.

Root cause

Frontend history mapping in EssaySubmission was ingesting all /api/essays/resources rows for an essay, without filtering to actual student submissions.

Corrective action

• Filter history rows to submission resources only:
  • objective includes student_submission, or
  • metadata contains uploaded_at, or
  • explicit submission timestamp exists.

Validation

• Frontend build succeeds after patch.
• History now excludes rubric/reference-only resources from the submission timeline.

Related: #139, #141