fix: inline purely structural generics

[alexchexes]

Partially closes #2233

---

When a type alias with generic parameters ultimately resolves to a purely structural type (no remaining type-parameters, no public reusable symbol), emitting it as a separate $ref just clutters the schema tree. This PR detects those cases and inlines the resolved structure directly into the parent definition, collapsing long reference chains and trimming unused definitions.

---

Examples

Case 1 — Mapped/Override helper

import { OverrideProperties } from "./util";

export type Base = {
    foo: string;
    bar: number;
};

export type MyType = OverrideProperties<
    Base,
    {
        bar: string;
    }
>;

Before

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "definitions": {
    "Base": { /* ... */ },
    "Merge<Base,structure-303496744-155-188-303496744-125-190-303496744-103-191-303496744-0-192>": {
      "$ref": "#/definitions/Simplify%3C(alias-1249507601-457-604-1249507601-0-1064%3Cdef-alias-1249507601-129-293-1249507601-0-1064%3Cdef-alias-303496744-44-103-303496744-0-192%3E%2Cdef-alias-1249507601-129-293-1249507601-0-1064%3Cstructure-303496744-155-188-303496744-125-190-303496744-103-191-303496744-0-192%3E%3E%26alias-1249507601-457-604-1249507601-0-1064%3Cdef-alias-1249507601-293-457-1249507601-0-1064%3Cdef-alias-303496744-44-103-303496744-0-192%3E%2Cdef-alias-1249507601-293-457-1249507601-0-1064%3Cstructure-303496744-155-188-303496744-125-190-303496744-103-191-303496744-0-192%3E%3E)%3E"
    },
    "MyType": {
      "$ref": "#/definitions/OverrideProperties%3CBase%2Cstructure-303496744-155-188-303496744-125-190-303496744-103-191-303496744-0-192%3E"
    },
    "OverrideProperties<Base,structure-303496744-155-188-303496744-125-190-303496744-103-191-303496744-0-192>": {
      "$ref": "#/definitions/Merge%3CBase%2Cstructure-303496744-155-188-303496744-125-190-303496744-103-191-303496744-0-192%3E"
    },
    "Simplify<(alias-1249507601-457-604-1249507601-0-1064<def-alias-1249507601-129-293-1249507601-0-1064<def-alias-303496744-44-103-303496744-0-192>,def-alias-1249507601-129-293-1249507601-0-1064<structure-303496744-155-188-303496744-125-190-303496744-103-191-303496744-0-192>>&alias-1249507601-457-604-1249507601-0-1064<def-alias-1249507601-293-457-1249507601-0-1064<def-alias-303496744-44-103-303496744-0-192>,def-alias-1249507601-293-457-1249507601-0-1064<structure-303496744-155-188-303496744-125-190-303496744-103-191-303496744-0-192>>)>": {
      "additionalProperties": false,
      "properties": {
        "bar": { "type": "string" },
        "foo": { "type": "string" }
      },
      "required": ["bar", "foo"],
      "type": "object"
    }
  }
}

After

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "definitions": {
    "Base": { /* ... */ },
    "MyType": {
      "additionalProperties": false,
      "properties": {
        "bar": { "type": "string" },
        "foo": { "type": "string" }
      },
      "required": ["bar", "foo"],
      "type": "object"
    }
  }
}

---

Case 2 — ValueOf on a const object

export const RuntimeObject = {
  FOO: "foo-val",
  BAR: "bar-val",
} as const;

export type ValueOf<T> = T[keyof T];

export type MyType = ValueOf<typeof RuntimeObject>;

Before

{
  "$ref": "#/definitions/MyType",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "definitions": {
    "MyType": {
      "$ref": "#/definitions/ValueOf%3Cobject-810933776-28-72-810933776-28-81-810933776-12-81-810933776-6-81-810933776-0-82-810933776-0-174%3E"
    },
    "ValueOf<object-810933776-28-72-810933776-28-81-810933776-12-81-810933776-6-81-810933776-0-82-810933776-0-174>": {
      "enum": ["foo-val", "bar-val"],
      "type": "string"
    }
  }
}

After

{
  "$ref": "#/definitions/MyType",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "definitions": {
    "MyType": {
      "enum": ["foo-val", "bar-val"],
      "type": "string"
    }
  }
}

---

Inlining these internal generics is safe: the generator already skips emitting them as standalone definitions - even if you'd request type: "OverrideProperties" - so this change only cleans the schema output without dropping any functionality.