JLSEC-2026-1353 Wasmtime can panic when adding excessive fields to a `wasi:http/types.fields` instance

Impact Wasmtime's implementation of the wasi:http/types.fields resource is susceptible to panics when too many fields are added to the set of headers. Wasmtime's implementation in the wasmtime-wasi-http crate is backed by a data structure which panics when it reaches excessive capacity and this...