082 reject bare effect catchall discard

// ============================================================================
// Test 210_082: MUST_FAIL — bare `!? |> _` effect catch-all is
//                          pay-for-nothing and must be parser-rejected.
//
// Symmetric with 210_081 for effect branches. Without `!?`, unhandled
// optional effect branches compile-time-elide (handler not installed in
// comptime struct → call lowers to nothing). With `!? |> _`, the consumer
// asks for unhandled effects to route into a no-op handler — runtime cost
// for zero information.
//
// Engagement rule applies identically to `!?` and `|?`: catch-all requires
// real work in the body, optionally informed by a metatype binding.
//
// Expected: parser rejects `!? |> _` with a message pointing at the
// catch-all line and explaining the no-engagement rule.
// ============================================================================

~pub event tokenize { source: []const u8 }
! token []const u8
! ?warning []const u8
! ?debug []const u8
| done usize

~pub event consume_token { t: []const u8 }
~pub event end_run { n: usize }

~tokenize(source: "x")
! token t |> consume_token(t: t)
!? |> _
| done n |> end_run(n: n)