070 reject terminal before effect at decl

// ============================================================================
// Test 210_070: MUST_FAIL — effect branches must precede terminal branches
//                          at the event declaration site.
//
// Per docs/EFFECT_BRANCHES.md: `!` (effect) branches always come first in
// source order at the declaration. The parser rejects any `|` (terminal)
// branch that appears above a `!` branch in the same event decl.
//
// Reasoning (doc):
//   Source order = temporal order. Effects during run, then how it ends.
//   Reader knows where to look: top = operations, bottom = termination.
//   Prevents accidentally pattern-matching a terminal and missing an
//   effect-handler in between.
// ============================================================================

~pub event for { start: usize, end: usize }
| done usize
! each usize