[zikk090]

SizeAlign::fill (and its internal calculate helper) computed the size of a FixedLengthList as element_size * length via checked_mul(..).unwrap(), which panics when the multiplication overflows usize. Since list<T, N> places no upper bound on N in the WIT text format (unlike the component binary format, which bounds it to MAX_WASM_FIXED_LENGTH_LIST_ELEMENTS), a WIT document with two nested fixed-length lists of a non-trivial element type is enough to overflow the multiplication and abort the process, in a release build too.

This changes SizeAlign::fill/calculate to return anyhow::Result and propagates that outward through wit-dylib's Adapter::encode, create, and create_with_metadata, and their two call sites (the wasm-tools wit-dylib CLI subcommand and the wit-dylib test-programs harness). A oversized fixed-length list now surfaces as a normal error instead of aborting:

$ wasm-tools wit-dylib poc.wit
error: size of fixed-length list of 4294967295 elements overflows
the target architecture's address space

Adds a regression test covering both the overflow case (now returns Err) and a benign nested fixed-length list (still computes correctly).

Fixes #2637

[pchickey]

Thank you! Please fix the error discovered by the clippy CI job. The other failure appears spurrious