Refactor for interface clarity and dependency isolation.

Replaced inline interface literals with dedicated, documented interface definitions in `pkg/interfaces/`. Introduced `TimeoutError`, `PolicyChecker`, and `Neo4jResultIterator` interfaces to clarify design, improve maintainability, and resolve potential circular dependencies. Updated config and constant usage rules for consistency. Incremented version to v0.31.11.

pkg/interfaces/neterr/neterr.go

@@ -0,0 +1,8 @@
+// Package neterr defines interfaces for network error handling.
+package neterr
+
+// TimeoutError is an interface for errors that can indicate a timeout.
+// This is compatible with net.Error's Timeout() method.
+type TimeoutError interface {
+	Timeout() bool
+}