feat: upgrade PaddlePaddle and PaddleOCR to 3.x

- Update paddlepaddle from >=2.5.0 to >=3.0.0,<3.3.0
- Update paddleocr from >=2.7.0 to >=3.0.0
- Update paddlepaddle-gpu from >=2.5.0 to >=3.0.0,<3.3.0

Note: PaddlePaddle 3.3.0 has an OneDNN bug that breaks CPU inference
(ConvertPirAttribute2RuntimeAttribute not implemented). Using <3.3.0
until the bug is fixed upstream.

This upgrade enables PP-StructureV3 for table extraction and uses
PP-OCRv5 for improved text recognition accuracy. The existing codebase
is already compatible with the 3.x API (predict() method and new
response format).

Verified:
- PaddleOCR import works
- PPStructureV3 is available
- OCREngine initializes correctly
- Inference API returns correct field extractions
- 2117 unit tests pass

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

pyproject.toml

@@ -25,8 +25,8 @@ classifiers = [
 
 dependencies = [
     "PyMuPDF>=1.23.0",
-    "paddlepaddle>=2.5.0",
-    "paddleocr>=2.7.0",
+    "paddlepaddle>=3.0.0,<3.3.0",
+    "paddleocr>=3.0.0",
     "ultralytics>=8.1.0",
     "Pillow>=10.0.0",
     "numpy>=1.24.0",
@@ -45,7 +45,7 @@ dev = [
     "testcontainers[postgres]>=4.0.0",
 ]
 gpu = [
-    "paddlepaddle-gpu>=2.5.0",
+    "paddlepaddle-gpu>=3.0.0,<3.3.0",
 ]
 
 [project.scripts]