embedInTokenBatches progress invariant

Every embedding path must use embedInTokenBatches, preserve input order, and call storeTemporalChunks once. The MAX_BATCH_TOKEN_AREA=4096 limit must always admit the first item even when it alone exceeds the area; rejecting it looks stricter but wedges the batching loop with no progress. Temporal input remains capped at 64 chunks by retaining 63 and joining the remainder into one tail.