Regression tests for the silent failure where callLambda returns a
Thunk (TCO) that must be trampolined for side effects to execute.
Without trampoline, event handlers (swap!, reset!) silently did nothing.
5 tests covering: single mutation, event arg passing, multi-statement
body, repeated accumulation, and nested lambda calls — all through
the (trampoline (call-lambda handler args)) pattern that dom-on uses.
Tests: 1322 JS (full), 1114 OCaml
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>