This commit introduces `BitColView` and `IntColView` to abstract over Columnar and Packed storage formats, implementing `BitSlice` and `IntSlice` for uniform column access. It adds `col_view()` accessors to `PersistentBitMatrix` and `PackedCompactIntMatrix`, explicitly panicking on implicit variants. The new types are publicly re-exported, and unit tests are added to validate per-element retrieval, aggregation methods, and parity with the original columnar representation.
Eric Coissac
93559c3294