feat: option to correct sideways scans

[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.)

Fixes #7768

This change adds Rotate Page 90° right and Rotate Page 90° left arrow buttons to the scanned-exam error correction page. Each click immediately updates the PDF preview by 90°, and the resulting rotation is applied permanently when the corrected scan is saved.

Screenshots of your changes (if applicable)

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

(Complete each of the following items for your pull request. Indicate that you have completed an item by changing the [ ] into a [x] in the raw text, or by clicking on the checkbox in the rendered description on GitHub.)

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

(Include any questions or comments you have regarding your changes.)

[coveralls]

Coverage Report for CI Build 30970627726

Coverage increased (+0.02%) to 90.604%

Details

• Coverage increased (+0.02%) from the base build.
• Patch coverage: 41 of 41 lines across 3 files are fully covered (100%).
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

---

Coverage Stats

Relevant Lines:	51638
Covered Lines:	47804
Line Coverage:	92.58%
Relevant Branches:	2491
Covered Branches:	1239
Branch Coverage:	49.74%
Branches in Coverage %:	Yes
Coverage Strength:	129.61 hits per line

---

💛 - Coveralls

[david-yz-liu]

Change to "Fix Page Orientation"

[david-yz-liu]

This is good; please also replace the screenshot below

[david-yz-liu]

This is good; the icons are a bit off-centre, please modify the vertical-align property for this class to fix the centering.

[david-yz-liu]

Nice work, @YheChen!