build(ci): bump zig to 0.15.1 and add more platforms

- Bump zig version to 0.15.1 and workaround zig fetch hang (ziglang/zig#24916)
- add mac os zig build (currently without luajit, linker failure)
- Add windows zig build, currently with very limited testing

src/gen/gen_api_dispatch.lua

@@ -171,7 +171,7 @@ local ui_options_text = nil
 for i = pre_args + 1, #arg do
   local full_path = arg[i]
   local parts = {} --- @type string[]
-  for part in full_path:gmatch('[^/]+') do
+  for part in full_path:gmatch('[^/\\]+') do
     parts[#parts + 1] = part
   end
   headers[#headers + 1] = parts[#parts - 1] .. '/' .. parts[#parts]

src/gen/gen_steps.zig

@@ -186,7 +186,7 @@ fn generate_header_for(
     } else {
         const h_file = gen_header(b, run_step, b.fmt("{s}.h.generated.h", .{basename}), gen_headers);
         if (api_export) |api_files| {
-            try api_files.append(h_file);
+            try api_files.append(b.allocator, h_file);
         }
     }