085 braced ctor payload inline bind

// Pin: the BRACED constructor payload in an inline bind-then-construct
// subflow (`producer(...): r => branch { r }`) is the same legal form as its
// braceless twin (302_subflow_flow / 100_053) and as the braced ctor in
// continuation position (compiler.kz's own emission chain ends
// `=> ctx { c3.ctx, c3.code }`). The parse must produce a fully-initialized
// AST — every field the Stage-A serializer walks must be defined — and the
// program must compile and run like its braceless twin.

const std = @import("std");

~event double { value: i32 } -> i32

~proc double|zig {
    return value * 2;
}

~event process { input: i32 } -> i32

~process = double(value: input): r -> { r }

~event print-result { value: i32 }

~proc print-result|zig {
    std.debug.print("{}\n", .{value});
}

~process(input: 21): f |> print-result(value: f)