feat(lib): add ScrollModel (numpy + ONNX Runtime); rename legacy scroll module

tests/unit/test_scroll.py

@@ -0,0 +1,37 @@
+"""Tests for ScrollModel and ai_mouse.generate_scroll()."""
+from __future__ import annotations
+
+import pytest
+
+
+def test_scroll_model_init_default() -> None:
+    from ai_mouse.scroll import ScrollModel
+    m = ScrollModel()
+    assert m._seq_len > 0
+    m.close()
+
+
+def test_scroll_model_generate_target_mode() -> None:
+    from ai_mouse.scroll import ScrollModel
+    m = ScrollModel()
+    events = m.generate(0, 1500, mode="target")
+    assert len(events) >= 5
+    total = sum(e["deltaY"] for e in events)
+    assert 1000 <= total <= 2000  # broad — quantisation can drift
+    assert events[0]["t"] == 0
+    assert all(e["deltaMode"] == 0 for e in events)
+
+
+def test_scroll_model_direction() -> None:
+    from ai_mouse.scroll import ScrollModel
+    m = ScrollModel()
+    events = m.generate(2000, 0, mode="target")
+    total = sum(e["deltaY"] for e in events)
+    assert total < 0
+
+
+def test_scroll_invalid_path() -> None:
+    from ai_mouse.errors import ModelLoadError
+    from ai_mouse.scroll import ScrollModel
+    with pytest.raises(ModelLoadError):
+        ScrollModel(model_path="/no/such/path")