Fix(paddleocr): load all PDF pages for image cropping instead of first 100 (#13811)

## Summary

Closes #13803

The `__images__` method in `paddleocr_parser.py` defaulted to
`page_to=100`, only loading the first 100 pages for image cropping.
However, the PaddleOCR API processes **all** pages of the PDF. For PDFs
with more than 100 pages, page indices beyond 99 were rejected as out of
range during crop validation, causing content loss.

## Root Cause

```
__images__(page_to=100) → loads pages 0-99 → page_images has 100 entries
PaddleOCR API → processes all 226 pages → tags reference pages 1-226
extract_positions() → converts tag "101" to index 100
crop() validation → 0 <= 100 < 100 → False → "All page indices [100] out of range"
```

## Fix

Changed `page_to` default from `100` to `10**9`, so all PDF pages are
loaded for cropping. Python's list slicing safely handles oversized
indices.

## Test plan

- [ ] Parse a PDF with >100 pages using PaddleOCR — no more "out of
range" warnings
- [ ] Parse a PDF with <100 pages — behavior unchanged
- [ ] Verify cropped images are generated correctly for all pages

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Asksksn <Asksksn@noreply.gitcode.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

deepdoc/parser/paddleocr_parser.py

@@ -422,7 +422,7 @@ class PaddleOCRParser(RAGFlowPdfParser):
         """Convert API response to table tuples."""
         return []
 
-    def __images__(self, fnm, page_from=0, page_to=100, callback=None):
+    def __images__(self, fnm, page_from=0, page_to=10**9, callback=None):
         """Generate page images from PDF for cropping."""
         self.page_from = page_from
         self.page_to = page_to