067 produce call on named arm emits void

// A `->` produce expression on a named branch arm whose whole value is a call
// (`| yes _ -> pack(id)`): the produce verifier forwards the callee's declared
// return contract, but the emitter drops the call's result — the arm emits
// `return void` where the produced record belongs (`expected type '...Output',
// found 'void'`). The shape should emit the call and produce its return value
// to the caller, obligation keys included (`res.h` owed `dispose` here).
~import std/io
const std = @import("std");
const Handle = struct { n: i32 };

~tor mint { id: usize } -> *Handle<owned!>
~proc mint|zig { const h = std.heap.page_allocator.create(Handle) catch unreachable; h.* = .{ .n = @intCast(id) }; return h; }

~tor dispose { h: *Handle<!owned> }
~proc dispose|zig { std.heap.page_allocator.destroy(h); }

~tor pack { id: usize } -> { h: *Handle<owned!>, n: i64 }
~pack = mint(id): h -> { h, n: 7 }

~tor gate { n: i64 } | yes i64 | no i64
~proc gate|zig { if (n > 0) return .{ .yes = n }; return .{ .no = n }; }

~tor spin { id: usize } -> { h: *Handle<owned!>, n: i64 }
~spin = gate(n: 1)
| yes _ -> pack(id)
| no _ -> pack(id)

~spin(id: 1): res |> dispose(res.h) |> std/io:print.ln("n={{ res.n:d }}")