Make page_size a runtime value

[lukewilliamboswell]

I added a WASM test harness for the Roc programming language Playground using Bytebox -- and our CI uncovered a bug in zig-stable-array,

Here is a gist with the original failure in CI from a ubuntu-24.04-arm machine

This change refactors StableArrayAligned to store page_size as an instance field rather than using a global, compile-time constant.

The page_size is now captured from heap.pageSize() in the init function and stored on the struct instance. All internal memory calculations have been updated to use this instance-specific page_size.

[rdunnington]

Hey thanks! I was able to repro the issue building bytebox with zig build -Dtarget=aarch64-linux-musl, which matches the same error you linked. I'll update bytebox main once this goes in. :)

I'm always interested to hear how people are using Bytebox - feel free to link me if/when the playground feature goes in.

[rdunnington]

Bytebox PR: rdunnington/bytebox#82

[isaacvando]

@rdunnington if you're interested, here's the current state of the playground