Guest debugging: track precise GC types in metadata

(Followup from [this discussion](https://github.com/bytecodealliance/wasmtime/pull/11769#discussion_r2426938721))

In the instrumentation-based guest debugging support, we have a separate `FrameValType` at the `environ` level that is used in the metadata to describe types of values. It is a mirror of the runtime-side types, but is simpler as it doesn't track precise GC types. We'll need to plumb through `ModuleInternedTypeIndex`es and then translate those via the type registry at runtime to support:

- Mutation, because we need to check that an updated value for a local/stack slot is of a compatible type
- An API that allows querying the precise type of the slot at runtime