WIP: feat: grades upload flow

[YheChen]

Proposed Changes

Adds CSV upload support for criterion marks from the assignment Grades tab.

This PR adds an Upload button for instructors on the assignment Grades tab. The upload flow accepts a CSV in the same general format as the existing Grades tab CSV export / grade entry form uploads, updates marks for matching assignment criteria, supports an overwrite option, and ignores total mark and bonus/deduction columns.

Also adds backend import handling, authorization, translations, and model/controller tests.

Fixes #7794

Screenshots of your changes (if applicable)

Add screenshots of:

• the new Upload button in the Grades tab
• the upload modal

Associated documentation repository pull request (if applicable)

N/A

Type of Change

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)
🔧 Internal (change that only affects developers or continuous integration)

Checklist

Before opening your pull request:

• I have performed a self-review of my changes.
  • Check that all changed files included in this pull request are intentional changes.
  • Check that all changes are relevant to the purpose of this pull request, as described above.
• I have added tests for my changes, if applicable.
  • This is required for all bug fixes and new features.
• I have updated the project documentation, if applicable.
  • This is required for new features.
• If this is my first contribution, I have added myself to the list of contributors.

After opening your pull request:

• I have updated the project Changelog (this is required for all changes).
• I have verified that the pre-commit.ci checks have passed.
• I have verified that the CI tests have passed.
• I have reviewed the test coverage changes reported by Coveralls.
• I have requested a review from a project maintainer.

Questions and Comments

Local pre-commit checks passed. Targeted frontend tests passed for assignment_summary.test.jsx.

[coveralls]

Coverage Report for CI Build 27793448111

Coverage increased (+0.02%) to 90.245%

Details

• Coverage increased (+0.02%) from the base build.
• Patch coverage: 5 uncovered changes across 4 files (172 of 177 lines covered, 97.18%).
• No coverage regressions found.

Uncovered Changes

File	Changed	Covered	%
app/javascript/Components/assignment_summary_table.jsx	3	1	33.33%
app/controllers/assignments_controller.rb	7	6	85.71%
app/javascript/Components/Modals/assignment_grades_upload_modal.jsx	4	3	75.0%
app/models/assignment.rb	67	66	98.51%
Total (8 files)	177	172	97.18%

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	50517
Covered Lines:	46579
Line Coverage:	92.2%
Relevant Branches:	2288
Covered Branches:	1075
Branch Coverage:	46.98%
Branches in Coverage %:	Yes
Coverage Strength:	126.17 hits per line

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💛 - Coveralls