fix: make OCR portable and reliable across AMD64 and ARM64 (#519)

* fix: make OCR portable and reliable

* fix: harden OCR installation portability

* fix: pin OCR partials across downloads

* fix: make OCR execution reliably asynchronous

* fix: harden OCR portability and docs routes

* fix: preserve decoder and docs safeguards

packages/ai/python/tests/test_ocr_runtime_isolation.py

@@ -0,0 +1,18 @@
+"""Accurate OCR must never re-enter the mutable legacy Python dispatcher."""
+
+from pathlib import Path
+
+from packages.ai.python import dispatcher
+
+
+def test_legacy_dispatcher_does_not_allow_ocr_scripts():
+    assert "ocr" not in dispatcher.ALLOWED_SCRIPTS
+    assert "ocr_pdf" not in dispatcher.ALLOWED_SCRIPTS
+
+
+def test_shared_requirements_do_not_install_paddle():
+    python_root = Path(__file__).resolve().parents[1]
+    for name in ("requirements.txt", "requirements-gpu.txt"):
+        requirements = (python_root / name).read_text(encoding="utf-8").lower()
+        assert "paddleocr" not in requirements
+        assert "paddlepaddle" not in requirements