fix: SDK API correctness — constructor, cypher() result, VectorResult fields

[polaz]

Bugs

• CoordinodeClient("host:port") — constructor doesn't parse host:port string, wrong gRPC target
• health() returns bool, tests expected dict.get("status")
• cypher() returns List[Dict[str, Any]], but LangChain/LlamaIndex/tests used .columns/.rows
• VectorResult has .node.id, .node.properties, .distance — tests used .node_id, .properties, .score
• test_types.py: _FakePV("vector", ...) should be "vector_value" to match from_property_value logic
• Unused imports flagged by ruff

Fix

• Add "host:port" parsing in AsyncCoordinodeClient.__init__
• Fix all callers in tests, langchain, llama-index to use actual API
• ruff clean