feat(ocr): improve text detection and OCR accuracy

Update OCR utils to handle different box formats and improve angle calculation
Modify PDF extraction kit to support OCR option and optimize processing flow
Enhance PPOCR model to sort and filter detection boxes, improving text splitting accuracy

Motivation

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Modification

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BC-breaking (Optional)

Does the modification introduce changes that break the backward compatibility of the downstream repositories? If so, please describe how it breaks the compatibility and how the downstream projects should modify their code to keep compatibility with this PR.

Use cases (Optional)

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Checklist

Before PR:

[ ] Pre-commit or other linting tools are used to fix the potential lint issues.
[ ] Bug fixes are fully covered by unit tests, the case that causes the bug should be added in the unit tests.
[ ] The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
[ ] The documentation has been modified accordingly, like docstring or example tutorials.

After PR:

[ ] If the modification has potential influence on downstream or other related projects, this PR should be tested with those projects.
[ ] CLA has been signed and all committers have signed the CLA in this PR.

opendatalab / MinerU