010 unselected variant rewrites mod

// Pins TWO things about a variant-selected tor that also carries an EFFECT arm.
//
// 1. `$mod.` is rewritten in EVERY variant body, not only the selected one.
//    Both bodies are emitted regardless of which is chosen, so an unselected
//    variant using `$mod.` shipped it verbatim into the Zig and failed the
//    build on a platform whose variant was never selected. FIXED.
//
// 2. RED, and the reason this test does not pass: an effect-bearing tor with
//    proc variants emits each variant as a STANDALONE `handler__<variant>`
//    function, whose body still calls the effect arm — `tick(...)` — which
//    does not exist in that scope. The effect arm is only in scope on the
//    inline-splice path the bare handler takes. So today an effect arm and a
//    proc variant cannot be combined at all, which is exactly what a
//    platform-selected event loop needs.
//
// A proc body that carries effect branches splices into its caller, so module
// scope is gone and KORU112 requires `$mod.<name>`. Both variant bodies are
// emitted into the binary regardless of which is selected — so an unselected
// variant using `$mod.` shipped it verbatim into the Zig, failing the build on
// a platform whose variant was never chosen.
//
// `alt` is never selected here. It must still compile.

~import std/io

const std = @import("std");
const factor: i32 = 10;

~tor pump { n: i32 }
! tick i32
| done string

~proc pump|zig {
    tick(n * $mod.factor);
    return .{ .done = "zig" };
}

~proc pump|alt {
    tick(n * $mod.factor * 2);
    return .{ .done = "alt" };
}

~tor drive { n: i32 }
| finished string
| blank

~drive =
    pump(n)
    ! tick _ |> _
    | done d -> finished d

~drive(n: 3)
| finished f |> std/io:print.ln(f)
| blank |> std/io:print.ln("blank")