Map SAB storage root safely

Only treat configured manual storage as Importarr-owned and map SAB container paths to local paths.

tests/test_sab_readiness.py

@@ -28,6 +28,30 @@ def test_wrong_category_outside_root_ignored():
     assert result.state == "ignored"
 
 
+def test_sab_storage_root_maps_to_local_download_root():
+    result = classify_history_item(
+        item(category="*", storage="/data/downloads/manual/Movie"),
+        set(),
+        "manual",
+        ROOT,
+        sab_storage_root=Path("/data/downloads/manual"),
+    )
+    assert result.ready
+    assert result.storage == ROOT / "Movie"
+
+
+def test_radarr_sonarr_storage_roots_are_not_importarr_owned():
+    for storage in ("/data/downloads/movies/Movie", "/data/downloads/tv/Show"):
+        result = classify_history_item(
+            item(category="*", storage=storage),
+            set(),
+            "manual",
+            ROOT,
+            sab_storage_root=Path("/data/downloads/manual"),
+        )
+        assert result.state == "ignored"
+
+
 def test_sab_cat_field_is_treated_as_category():
     result = classify_history_item(item(category=None, cat="manual"), set(), "manual", ROOT)
     assert result.ready