chore: 添加虚拟环境到仓库

- 添加 backend_service/venv 虚拟环境
- 包含所有Python依赖包
- 注意：虚拟环境约393MB，包含12655个文件

backend_service/venv/lib/python3.13/site-packages/chromadb/test/db/test_log_purge.py

@@ -0,0 +1,50 @@
+from chromadb.api.client import Client
+from chromadb.config import System
+from chromadb.test.property import invariants
+
+
+def test_log_purge(sqlite_persistent: System) -> None:
+    client = Client.from_system(sqlite_persistent)
+
+    first_collection = client.create_collection(
+        "first_collection", metadata={"hnsw:sync_threshold": 10, "hnsw:batch_size": 10}
+    )
+    second_collection = client.create_collection(
+        "second_collection", metadata={"hnsw:sync_threshold": 10, "hnsw:batch_size": 10}
+    )
+    collections = [first_collection, second_collection]
+
+    # (Does not trigger a purge)
+    for i in range(5):
+        first_collection.add(ids=str(i), embeddings=[i, i])
+
+    # (Should trigger a purge)
+    for i in range(100):
+        second_collection.add(ids=str(i), embeddings=[i, i])
+
+    # The purge of the second collection should not be blocked by the first
+    invariants.log_size_below_max(client._system, collections, True)
+
+
+def test_log_purge_with_multiple_collections(sqlite_persistent: System) -> None:
+    client = Client.from_system(sqlite_persistent)
+
+    first_collection = client.create_collection(
+        "first_collection", metadata={"hnsw:sync_threshold": 10, "hnsw:batch_size": 10}
+    )
+    second_collection = client.create_collection(
+        "second_collection", metadata={"hnsw:sync_threshold": 10, "hnsw:batch_size": 10}
+    )
+    collections = [first_collection, second_collection]
+
+    # (Does not trigger a purge)
+    for i in range(15):
+        first_collection.add(ids=str(i), embeddings=[i, i])
+
+    # (Should trigger a purge)
+    for i in range(25):
+        second_collection.add(ids=str(i), embeddings=[i, i])
+
+    invariants.log_size_for_collections_match_expected(
+        client._system, collections, True
+    )