### What problem does this PR solve?
Improve image table context.
Current strategy in attach_media_context:
- Order by position when possible: if any chunk has page/position info,
sort by (page, top, left), otherwise keep original order.
- Apply only to media chunks: images use image_context_size, tables use
table_context_size.
- Primary matching: on the same page, choose a text chunk whose vertical
span overlaps the media, then pick the one with the closest vertical
midpoint.
- Fallback matching: if no overlap on that page, choose the nearest text
chunk on the same page (page-head uses the next text; page-tail uses the
previous text).
- Context extraction: inside the chosen text chunk, find a mid-sentence
boundary near the text midpoint, then take context_size tokens split
before/after (total budget).
- No multi-chunk stitching: context comes from a single text chunk to
avoid mixing unrelated segments.
### Type of change
- [x] Refactoring
---------
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>
### What problem does this PR solve?
Fix：Bugs Fixed
- Text overflow issues that caused rendering problems
- Metadata saving, copywriting and other related issues
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
feature: Complete metadata functionality
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Only support MinerU-API now, still need to complete frontend for
pipeline to allow the configuration of MinerU options.
### Type of change
- [x] Refactoring
### What problem does this PR solve?
Change the data in the dataset page to be obtained using the interface,
and change the import to obtain all data every 15 seconds to obtain the
data of the current page every 5 seconds when parsing the existing file.
[#3221](https://github.com/infiniflow/ragflow/issues/3221)
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
Feat: Display the knowledge graph on the knowledge base page #4543
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Metadata in documents for improve the prompt #3690
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
fix: Change document status with @tanstack/react-query #13306
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
- [ ] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):
### What problem does this PR solve?
feat: Supports chatting with files/images #1880
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
