Enhance Store DX: Add 'init' parameter to add() and insert() for immediate record creation

Improve DX by allowing Neo.data.Store to return fully instantiated records directly from add() and insert().

Proposal: Overload add() and insert() in Neo.data.Store with an optional second parameter init=false.

1. add(items, init=false)

   • If init is true, the method should return an Array of Record instances instead of the raw data objects.
   • It effectively combines add(items) + initRecord(item) for each added item.

2. insert(index, items, init=false)

   • Similarly, allow insert to optionally initialize and return the created records.

Reasoning: Currently, lazy records requires a two-step process to get a usable Record instance:

store.add(data);
const record = store.get(id); // Required to get the Record

This change simplifies it to:

const [record] = store.add(data, true);

Architectural Note: This overloads the collection.Base signature. While slightly impure, the DX benefit for Store usage is significant.