feat(scenegraph): add SoftwareCamIndex for visual hash similarity queries

- Add SoftwareCamIndex class with xnor_popcount_score for CAM-style matching
- Add CamMatch and SceneGraphMatch dataclasses for query results
- Add query_by_visual_hash method to SimpleSceneGraph
- Add comprehensive tests for SoftwareCamIndex and xnor_popcount_score

mini-nav/scenegraph/scenegraph.py

@@ -1,10 +1,42 @@
 from dataclasses import dataclass, field
 
-from .roomnode import RoomNode
 from .objectnode import ObjectNode
+from .roomnode import RoomNode
+
+
+@dataclass(frozen=True)
+class SceneGraphMatch:
+    obj_id: str
+    node: ObjectNode
+    row_index: int
+    score: int
+    similarity: float
+    hash_bytes: bytes
 
 
 @dataclass
 class SimpleSceneGraph:
     rooms: dict[str, RoomNode] = field(default_factory=dict)
     objects: dict[str, ObjectNode] = field(default_factory=dict)
+
+    def query_by_visual_hash(
+        self,
+        query_hash_bytes: bytes,
+        *,
+        top_k: int = 1,
+    ) -> list[SceneGraphMatch]:
+        from .software_cam import SoftwareCamIndex
+
+        index = SoftwareCamIndex.from_scene_graph(self)
+        cam_matches = index.query(query_hash_bytes, top_k=top_k)
+        return [
+            SceneGraphMatch(
+                obj_id=match.obj_id,
+                node=self.objects[match.obj_id],
+                row_index=match.row_index,
+                score=match.score,
+                similarity=match.similarity,
+                hash_bytes=match.hash_bytes,
+            )
+            for match in cam_matches
+        ]