[Bug]: GetLine returns raw number for NominalValue but types declare IfcValue

[cassus]

What happened?

GetLine() returns a raw JavaScript number for IfcPropertySingleValue.NominalValue, but TypeScript types declare IfcValue | null.

TypeScript types (web-ifc-api.d.ts):

NominalValue: IfcValue | null
// where IfcValue = IfcMeasureValue | IfcSimpleValue | IfcDerivedMeasureValue

Runtime behavior:

typeof readProp.NominalValue === "number"  // true
readProp.NominalValue instanceof IFC4X3.IfcInteger  // false
readProp.NominalValue  // 7 (raw number, not wrapper)

This mismatch causes TypeScript code to fail at runtime when pattern matching on IfcValue types.

String types (IfcText, IfcLabel) and booleans (IfcBoolean) retain their wrappers - only numeric types return raw primitives.

Minimal reproduction

import { IFC4X3, IfcAPI } from "web-ifc"

const api = new IfcAPI()
await api.Init()
const modelID = api.CreateModel({ schema: "IFC4X3" })

// Create property with IfcInteger value
const prop = new IFC4X3.IfcPropertySingleValue(
  new IFC4X3.IfcIdentifier("TestProperty"),
  null,
  new IFC4X3.IfcInteger(7),
  null
)

// Before write: proper wrapper
console.log(prop.NominalValue instanceof IFC4X3.IfcInteger) // true
console.log((prop.NominalValue as IFC4X3.IfcInteger).value) // 7

// Write to model
api.WriteLine(modelID, prop)

// Read back
const readProp = api.GetLine(modelID, prop.expressID) as IFC4X3.IfcPropertySingleValue

// After read: raw number instead of wrapper
console.log(readProp.NominalValue instanceof IFC4X3.IfcInteger) // false ❌
console.log(typeof readProp.NominalValue) // "number"
console.log(readProp.NominalValue) // 7 (value preserved, type lost)

api.CloseModel(modelID)

This causes issues because TypeScript types declare NominalValue as IfcValue | null, but runtime returns raw primitives for numeric types.

Version

0.0.72

What browsers are you seeing the problem on?

None (Node.js environment)

Anything else?

Related to #1561 but different symptom:

• [Bug]: The type of the NominalValue parameter in the IfcPropertySingleValue attribute is lost when read using the GetLine method. #1561: NominalValue becomes null (data loss)
• This issue: NominalValue is 7 (value preserved, type wrapper lost)

The type definitions in web-ifc-api.d.ts declare NominalValue as IfcValue | null which doesn't include raw primitives, causing type mismatches at runtime.