Nonnegative seeded extension inside/outside computation. Paths belong to their left-most seed after removing containing occurrences. This is also the first completed seed, choosing the shortest co-ending seed: a containing seed cannot complete first, and remaining overlapping stacks have the same start and end order. Exact and heuristic prediction share seed-local tables joining seed-avoiding left extensions to unrestricted right extensions. A heuristic selector keeps one right endpoint for true two-sided extensions and retains every one-sided extension. Complete boundaries are accumulated in bounded batches; anchors crossing batches are recomputed. Batches without the seed's own start as a source need right tables only up to the chosen endpoint. Native energy ownership is supplied by the adapter: initiation once, one transition per successive pair, one boundary factor. All callbacks must be deterministic; zero denotes forbidden weight.
