Display mark last updated by

[akarki2005]

Proposed Changes

Displays who last graded (updated the mark for) a criterion in the grading view, visible only to TAs and instructors. This mirrors the existing "creator"/"last editor" pattern already used for annotations.

The last_updated_by association on Mark already existed on the backend (#7878, #7885) but wasn't exposed anywhere in the UI. This PR:

• Adds last_updated_by to the marks payload returned by ResultsController#show, gated behind the same TA/instructor/reviewer check already used for annotation creator visibility (can_view_grader_info), so students never receive this data at all.
• Updates ResultsController#update_mark's JSON response to include last_updated_by, and patches local React state in result.jsx so the UI updates immediately after a mark change, without a reload.
• Displays a small caption ("Last updated by ") under the mark for checkbox, flexible, and rubric criteria, hidden once results are released to students.

Screenshots

Type of Change

(Write an X or a brief description next to the type or types that best describe your changes.)

Type	Applies?
🚨 Breaking change (fix or feature that would cause existing functionality to change)
✨ New feature (non-breaking change that adds functionality)	X
🐛 Bug fix (non-breaking change that fixes an issue)
🎨 User interface change (change to user interface; provide screenshots)	X
♻️ Refactoring (internal change to codebase, without changing functionality)
🚦 Test update (change that only adds or modifies tests)
📦 Dependency update (change that updates a dependency)
📖 Documentation update (change that updates documentation)
🔧 Internal (change that only affects developers or continuous integration)

Checklist

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[coveralls]

Coverage Report for CI Build 32160271930

Coverage remained the same at 90.632%

Details

• Coverage remained the same as the base build.
• Patch coverage: 27 of 27 lines across 2 files are fully covered (100%).
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	51799
Covered Lines:	47967
Line Coverage:	92.6%
Relevant Branches:	2500
Covered Branches:	1245
Branch Coverage:	49.8%
Branches in Coverage %:	Yes
Coverage Strength:	129.7 hits per line

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💛 - Coveralls