fix: typebox object schemas without properties key

[0xthierry]

This PR fixes a TypeError in hasAdditionalProperties when handling intersection types that include a TypeBox Record. The function fails when processing schemas that have type: "object" but no properties key.

Issue

When using an intersection (Type.Intersect) with a Record type from TypeBox, the generated schema is a valid JSON Schema object using allOf, but lacks a properties key in some of its subschemas. This causes hasAdditionalProperties to throw a TypeError when attempting to access the properties field.

Example schema that triggers the bug:

{
  "allOf": [
    {
      "type": "object",
      "properties": {
        "a": {
          "type": "string"
        }
      },
      "required": ["a"]
    },
    {
      "type": "object",
      "patternProperties": {
        "^(0|[1-9][0-9]*)$": {
          "type": "string"
        }
      }
    }
  ]
}

Tests

Added test case for intersection of object + record types
Verified handling of schemas with missing properties key