feat: toggle submissions table

[YheChen]

Proposed Changes

(Describe your changes here. Also describe the motivation for your changes: what problem do they solve, or how do they improve the application or codebase? If this pull request fixes an open issue, use a keyword to link this pull request to the issue.)

Ref #6424

This PR allows graders with the manage submissions permission to toggle the submissions table between:

• all submissions for the assignment
• only submissions assigned to them

This mirrors the existing inactive-groups toggle pattern in the submissions table. The backend now includes an assigned flag in submission table data for managed graders, while graders without manage-submissions permission continue to only receive their assigned submissions. The submissions table uses that flag for a hidden filter column and exposes a new “Display assigned submissions only” checkbox only when applicable.

Tests were added for both the React table filtering behavior and the assignment submission-data contract.

Screenshots of your changes (if applicable)

Type of Change

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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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Questions and Comments

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[coveralls]

Coverage Report for CI Build 28990180113

Coverage increased (+0.005%) to 90.291%

Details

• Coverage increased (+0.005%) from the base build.
• Patch coverage: 33 of 33 lines across 3 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:	51052
Covered Lines:	47108
Line Coverage:	92.27%
Relevant Branches:	2454
Covered Branches:	1203
Branch Coverage:	49.02%
Branches in Coverage %:	Yes
Coverage Strength:	127.37 hits per line

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💛 - Coveralls