fix(perception): disable PaddleOCR doc-unwarping for screenshots

PaddleOCR's OCR.yaml pipeline defaults to use_doc_orientation_classify
and use_doc_unwarping enabled, which are meant for photographed paper
documents. Applied to a flat, upright device screenshot, UVDoc
geometrically warps the image before detection, and returns box
coordinates in that warped space with no inverse mapping back to the
original image.

Verified on a real screenshot: with unwarping on, the same detected
element ("新项目") shifts from y=158 to y=71 versus the original image,
and 2 boxes near the top edge (status bar time/battery) are dropped
entirely. Disabling both flags by default (still overridable via
explicit kwargs) makes detected boxes match the original screenshot.

tests/test_ocr.py

@@ -4,7 +4,24 @@ import numpy as np
 import pytest
 
 from core.models import Bounds
-from perception.ocr import OCRBox, parse_paddle_result, run_ocr
+from perception.ocr import OCRBox, PaddleOCREngine, parse_paddle_result, run_ocr
+
+
+def test_paddle_ocr_engine_disables_doc_preprocessing_by_default() -> None:
+    # Screenshots are flat, upright digital captures, not photographed paper
+    # documents: PaddleOCR's document-unwarping preprocessing has nothing real
+    # to correct and instead warps the image, so detected box coordinates no
+    # longer line up with the original screenshot.
+    engine = PaddleOCREngine(lang="ch")
+
+    assert engine.kwargs["use_doc_orientation_classify"] is False
+    assert engine.kwargs["use_doc_unwarping"] is False
+
+
+def test_paddle_ocr_engine_lets_callers_override_doc_preprocessing() -> None:
+    engine = PaddleOCREngine(use_doc_unwarping=True)
+
+    assert engine.kwargs["use_doc_unwarping"] is True
 
 
 def test_parse_paddle_result_accepts_ndarray_fields() -> None: