fix(memory): strip type field from entities/relations in loadGraph

[jared03]

Summary

Fixes schema validation error in read operations (read_graph, search_nodes, open_nodes).

Problem

The JSONL file stores entities with a type field to distinguish them from relations:

{"type":"entity","name":"...","entityType":"...","observations":[...]}

But the output schema only expects {name, entityType, observations} - no type field.

This causes all read operations to fail with:

MCP error -32602: Structured content does not match the tool's output schema: data.entities[0] should NOT have additional properties

Solution

Strip the type field using destructuring before pushing to result arrays:

if (item.type === "entity") {
  const { type, ...entity } = item;
  graph.entities.push(entity as Entity);
}
if (item.type === "relation") {
  const { type, ...relation } = item;
  graph.relations.push(relation as Relation);
}

Testing

• All 39 existing tests pass
• All read operations now return valid responses
• Write operations continue to work correctly
• Existing JSONL files remain fully compatible

Fixes #3074