085 obligation held across back edge

// PINS (held-across): an obligation OWNED in the same scope as a label-fold is
// NOT the loop's to consume — the fold runs over a SCALAR (never touches the
// handle), and the handle is escaped on the exit branch's bare return. h0 is
// live (uncleaned) at `@loop(c: c2)` but is held across and escaped on `fin`;
// the escape `-> h0` re-issues it through spin's `-> *Handle<owned!>` return,
// so the caller's dispose is the one discharge. No disposal belongs inside the
// fold's exit arm.
//
// Spelled with branch arms per 510_109's ruling (an inline `: v` on a branching
// tor is KORU022); the carry shape mirrors green 330_074.
const std = @import("std");
const Handle = struct { n: i32 };

~tor make {} -> *Handle<owned!>
~proc make|zig {
    const h = std.heap.page_allocator.create(Handle) catch unreachable;
    h.* = .{ .n = 0 };
    return h;
}

~tor icount { c: i32 }
| more i32
| fin i32
~proc icount|zig {
    if (c < 3) return .{ .more = c + 1 };
    return .{ .fin = c };
}

~tor dispose { h: *Handle<!owned> }
~proc dispose|zig {
    std.debug.print("n={}\n", .{h.n});
    std.heap.page_allocator.destroy(h);
}

~tor spin {} -> *Handle<owned!>

~spin = make(): h0 |> #loop icount(c: 0)
    | more c2 |> @loop(c: c2)
    | fin _ -> h0

~spin(): hf |> dispose(h: hf)