Pluggable strategy for executing sandbox code. The default
mainThreadExecutor compiles + runs in the host realm; an alternative
executor (e.g. the iframe-worker one) can run the same code in a locked-down
realm off the main thread while honouring this exact contract.
run MUST resolve to { value } or { error } and never reject — execution
failures are reported as { error } via formatSandboxExecutionError.
Pluggable strategy for executing sandbox code. The default mainThreadExecutor compiles + runs in the host realm; an alternative executor (e.g. the iframe-worker one) can run the same code in a locked-down realm off the main thread while honouring this exact contract.
runMUST resolve to{ value }or{ error }and never reject — execution failures are reported as{ error }via formatSandboxExecutionError.