fix: CI typo, Rust lint, NaN preservation, C++ includes, Go tests

Closes #28 — replace goto-bus/setup-zig with mlugg/setup-zig in both
test-bindings.yml and release.yml.

Closes #35 — add #![allow(non_camel_case_types)] to goldenfloat-sys
lib.rs for FFI-style type names.

Closes #38 — GF16.fromF32 now maps NaN to exp=0x3F,mant=1 (not inf).
GF16.toF32 returns std.math.nan when exp=0x3F and mant!=0.

Closes #36 — add cpp/include to CMakeLists include_directories so
<goldenfloat/gf16.hpp> resolves.

Closes #37 — remove import "C" from gf16_test.go (Go forbids cgo
in test files). Rewrite tests as exported Test* functions using the
Go wrapper API from gf16.go.

Author: gHashTag

.github/workflows/release.yml

@@ -40,7 +40,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Setup Zig
-        uses: goto-bus-stop/setup-zig@v2
+        uses: mlugg/setup-zig@v2
         with:
           version: 0.15.0
 

.github/workflows/test-bindings.yml

@@ -31,7 +31,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Zig
-        uses: goto-bus/setup-zig@v2
+        uses: mlugg/setup-zig@v2
         with:
           version: 0.15.2