Function getAmbientDeadline

src/common/interruptible.ts:48–50

()

   * canonicalization on a DIFFERENT engine — reachable because a canonical
   * handler runs arbitrary caller code — consumes stride boundaries while the
   * engine being checked at that moment has no frame armed. The check is then
   * a no-op and the engine that DOES have a budget waits up to another full
   * stride, so the residual overrun is not the one stride the walk claims.
   * A frame is created per `withTimeLimit` span, so per-frame ticking makes
   * that bound exact, at the cost of one property access.
   */