feat: implement PP-Structure table extraction pipeline with GPU runtime configuration support

tests/unit/test_table.py

@@ -2,8 +2,12 @@
 
 from __future__ import annotations
 
+import sys
+from types import ModuleType, SimpleNamespace
+
 import pytest
 
+from ocr_sprint.pipeline import table as table_module
 from ocr_sprint.pipeline.table import (
     DetectedTable,
     extract_tables_from_pp_result,
@@ -82,6 +86,34 @@ class TestDetectedTable:
         assert table.n_cols == 0
 
 
+class TestPpStructureInit:
+    def test_gpu_init_falls_back_to_cpu(self, monkeypatch: pytest.MonkeyPatch) -> None:
+        calls: list[dict[str, object]] = []
+
+        class FakePPStructure:
+            def __init__(self, **kwargs: object) -> None:
+                calls.append(kwargs)
+                if kwargs["use_gpu"]:
+                    raise RuntimeError("gpu init failed")
+
+        fake_paddleocr = ModuleType("paddleocr")
+        fake_paddleocr.PPStructure = FakePPStructure
+        monkeypatch.setitem(sys.modules, "paddleocr", fake_paddleocr)
+        monkeypatch.setattr(
+            table_module,
+            "get_settings",
+            lambda: SimpleNamespace(ocr_lang="latin", ocr_use_gpu=True),
+        )
+
+        engine = table_module._build_pp_structure()
+
+        assert isinstance(engine, FakePPStructure)
+        assert calls == [
+            {"lang": "en", "use_gpu": True, "layout": True, "show_log": False},
+            {"lang": "en", "use_gpu": False, "layout": True, "show_log": False},
+        ]
+
+
 @pytest.fixture
 def sample_personnel_table() -> DetectedTable:
     """Header + three personnel rows in a typical Polres-level format."""