Improve the `ValueParser` to correctly disambiguate between empty
arrays `[]` and the start of nested structures. This ensures that
the parser can distinguish between an array containing a single
element that starts with a bracket and an actual empty array.
Update tests to reflect that parsed tuples are returned as arrays
rather than objects.
Split the monolithic `src/csv-loader/loader.test.ts` into multiple
specialized test files to improve maintainability and readability:
- `parseCsv-basic.test.ts`: Primitive types, arrays, and tuples
- `parseCsv-caching.test.ts`: Table caching logic
- `parseCsv-circular.test.ts`: Circular reference detection
- `parseCsv-combinators.test.ts`: References in unions and tuples
- `parseCsv-noResolveRefs.