fix: compare included files with path semantics

[vortsghost2025]

Fixes #638.

Problem

On Windows, wildcard ("*") schema generation can silently return an empty definitions object when glob and TypeScript represent the same source path with different separators.

Observed for the same file:

glob:       schema\draft\schema.ts
TypeScript: schema/draft/schema.ts

exact string equality: false
pathEqual:             true

buildGenerator() currently uses exact string membership, which can leave userSymbols empty even though named symbols remain available.

Fix

Use the existing pathEqual() helper:

- return onlyIncludeFiles.indexOf(file.fileName) >= 0;
+ return onlyIncludeFiles.some((f) => pathEqual(f, file.fileName));

The library already uses pathEqual() for a related comparison in getMainFileSymbols().

Regression test

Adds a focused test using opposite slash styles for the same source file and verifies that it is still classified as a user/main-file source.

No workflow or schema-tooling changes.

Windows validation

Validated while investigating modelcontextprotocol/modelcontextprotocol#3114 with typescript-json-schema 0.68.0.

Fresh Windows generation after this one-line fix produced:

2024-11-05     79 definitions
2025-03-26     83 definitions
2025-06-18     91 definitions
2025-11-25    145 definitions
2026-07-28    155 definitions
draft         155 definitions

The regenerated schema files had no diff from the checked-in schemas.

Example validation:

Results: 258 passed, 0 failed