startMutationObserver function ✓ 100.0%

function startMutationObserver(): void {
  if (mutationObserver) return;

  mutationObserver = new MutationObserver((mutations) => {
    if (!session || session.status !== "recording") return;

    // Debounce rapid mutations
    if (pendingMutationTimer) clearTimeout(pendingMutationTimer);
    pendingMutationTimer = setTimeout(() => {
      processMutations(mutations);
    }, MUTATION_DEBOUNCE_MS);
  });

  mutationObserver.observe(document.body, {
    childList: true,
    subtree: true,
    attributes: true,
    attributeFilter: ["style", "class", "hidden", "disabled", "aria-hidden"],
  });
}