subflow invalid branch

// PINS: a subflow continuation naming a branch the invoked tor does not declare
// is rejected (KORU021), in SUBFLOW position — the flow head is `process = …`,
// not a top-level call.
//
// `double` declares `doubled` and `refused`. The third arm names `tripled`,
// which is neither.
//
// The callee must be a BRANCHED tor for this pin to mean anything: a bare-return
// `-> T` tor carries no branch tags at all, so `| <label>` on one is binding
// sugar and "has no branch" is not a claim the language makes about it
// (flow_checker.zig:1462). This file spelled `double` as a one-branch tor until
// the lone-payload burn-down (3c77223f) rewrote every such tor into a bare
// return — which moved the program off the shape the pin names. Two branches,
// so the shape is expressible under the current rule.
const std = @import("std");

~tor double { value: i32 }
| doubled i32
| refused string

~proc double|zig {
    if (value < 0) return .{ .refused = "negative" };
    return .{ .doubled = value * 2 };
}

~tor process { input: i32 }
| final i32
| stopped string

~process = double(value: input)
| doubled d => final d
| refused r => stopped r
| tripled t => final t