feat(backend): knowledge iteration + vision + neo4j + response contract source

dependencies.py 拆分为 dependencies/ 包; 新增 vision/ragflow_ingestion/neo4j 客户端与 h5_ai_task; alembic 045 图置信度迁移; 响应契约统一收尾。

backend/app/services/__init__.py

@@ -12,6 +12,13 @@ from app.services.session_service import SessionService
 from app.services.funny_phrase_service import FunnyPhraseService
 from app.services.ai_handler import AIHandler
 
+# Tier0 新增服务导出
+from app.services.neo4j_client import Neo4jClient, dep_neo4j_client, get_neo4j_client
+from app.services.knowledge_iteration_service import KnowledgeIterationService, dep_knowledge_iteration_service
+from app.services.wingman_service import WingmanService
+from app.services.vision_service import VisionService
+from app.services.ragflow_ingestion_service import RagflowIngestionService
+
 __all__ = [
     "WecomService",
     "MessageRouter",
@@ -19,4 +26,13 @@ __all__ = [
     "SessionService",
     "FunnyPhraseService",
     "AIHandler",
+    # Tier0
+    "Neo4jClient",
+    "dep_neo4j_client",
+    "get_neo4j_client",
+    "KnowledgeIterationService",
+    "dep_knowledge_iteration_service",
+    "WingmanService",
+    "VisionService",
+    "RagflowIngestionService",
 ]