Struct StateKernelCtxFields 

#[repr(C)]
pub struct StateKernelCtxFields {
    pub arena_resolution_cb: extern "C" fn(handle: SimHandle, net: SlotId),
    pub vc_side_channel: *mut c_void,
}

ST-131: this struct names only the fields STATE owns. The full KernelCtx a compiled kernel actually receives (current sim time, the rest of the suspend/resume contract) is jointly defined by ENGINE/CODEGEN and is out of this crate’s scope — it is not redefined here. This is a documented sub-shape other tracks’ real KernelCtx embeds (by value or by reference), never a claim that STATE owns or defines the whole thing.

• arena_resolution_cb: the resolution-callback vtable slot ARCHITECTURE §6.2 / state.md §3 name as jointly owned — the entry point a compiled kernel calls to resolve a net read through STATE’s own multi-driver resolution (driver::resolve_net_step), rather than reading a slot directly. Its exact wiring to a real elaborated net is out of this wave’s scope (see the plan’s Deferred section, NetKind gap); this field only names the calling-convention slot, not a live implementation of it.
• vc_side_channel: an opaque pointer to this crate’s speculative-buffer append point (Task 8’s [VcState]) — the mechanism a compiled kernel’s write path reaches to append a VcRecord, without STATE handing the kernel anything more specific than an opaque handle it round-trips back through STATE’s own accessor ABI.

#[repr(C)]: this struct’s fields are the exact bytes a compiled-kernel calling convention embeds, so its layout must be FFI-stable — no field reordering/padding a Rust-only #[repr(Rust)] struct would otherwise be free to apply.

Fields

arena_resolution_cb: extern "C" fn(handle: SimHandle, net: SlotId)

vc_side_channel: *mut c_void