isSingleParenOrIifeExpression accepted any tail after the initial group's
close as long as trailing chars looked chain-ish, so
`(async()=>{await 1})().then(x=>x); console.log('done')` classified as a
single expression and the expression wrapper emitted a SyntaxError. The
tail is now consumed as a strict member/call/index/optional-chain walk to
END of input via a shared string/escape-aware findBalancedClose scanner;
anything else (';', operators) demotes to the block wrapper. Negative +
positive tests added.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Wave-amended: test moved to browse/test/ (browse unit-test convention); trailing-semicolon normalization kept — it is load-bearing for the expression wrapper
