forked from unom/punktfunk
#![forbid(unsafe_code)] on both crates. Upstream's codec module was one production unsafe away: build_ref_pic_lists turned DPB borrows into indices via pointer offset_from — same pointer-identity mapping now expressed as position(ptr::eq) over the <=16-entry DPB (PROVENANCE #5). Three test-only mem::zeroed() asserts became Default::default(), an identical value for the all-integer PredWeightTable. Honest coverage note: build_ref_pic_lists has no callers inside the vendored subset (its consumer was the non-vendored stateless layer), so the rewrite is equivalence-by-construction until the DecodePlan layer exercises it against goldens.