Support mixed top-level f32 native signatures #1029

Summary

Allow bound native functions to mix top-level f32 arguments with integer, pointer, aggregate, and other top-level argument types.

Why

C ABI types are exact: replacing a C float with f64 changes the signature and is not a valid workaround. The raylib 6.0 binding generator currently skips 109 functions for this reason, leaving 488 callable functions and a post-fix target of 597. See the merged skip report.

Current behavior

On current main (34cc32f):

const lib = FFI.open("./fixtures/ffi/libfixture" + FFI.suffix);
lib.bind("get_answer", {
  args: ["i32", "f32"],
  returns: "i32",
});

Binding throws:

f32 arguments cannot be mixed with other types. Use f64 instead, or keep all arguments f32

Current-source evidence:

• ParseSignatureFromArgs rejects mixed top-level f32.
• The ABI validator carries the same restriction.
• The focused regression test explicitly expects the bind to throw.
• The public FFI reference documents the limit.

The fresh-main FFI suite passes in interpreted and bytecode modes (92 tests, 337 assertions), confirming this is the current documented contract rather than stale release behavior.

Expected behavior

A signature such as ["i32", "f32"] should bind and invoke with the platform's native ABI classification. Add native-fixture coverage for mixed f32 positions and representative integer, pointer, and aggregate neighbors in both execution modes.

Scope notes

• This belongs to the optional FFI runtime extension, not the JavaScript parser or language syntax.
• Do not substitute f64 for native float parameters.
• Related: Add explicit FFI support for native shared libraries #178, FFI v2 #827, and GocciaScript-Raylib PR #7.