refactor: rename obikpartitionner crate to obikpartition

Update Cargo manifests, dependency paths, and Rust imports across the workspace to reflect the `obikpartitionner` to `obikpartition` rename. Synchronize architecture and implementation documentation with the new module structure. Fix minor syntax issues in test assertions to ensure compilation compatibility. No behavioral or API changes are introduced.

DevDocMD/architecture/siblings.md

@@ -770,7 +770,7 @@ reproducible across two runs with warm disk cache), the opposite of
 query").
 
 **Root cause, read from source, not measured in isolation:**
-`KmerPartition::query_partition_with` (`obikpartitionner/src/query_layer.rs:155-220`)
+`KmerPartition::query_partition_with` (`obikpartition/src/query_layer.rs:155-220`)
 is architecturally column-major: stage 2 walks `for g in 0..n_cols { for
 slot in hit_slots { layer.col_value(g, slot) } }`, documented (correctly)
 as the right locality strategy for the packed/columnar formats, where
@@ -914,7 +914,7 @@ replaces.
   `PersistentCompactIntMatrix::nonzero_iter` added the same way (counts
   not excluded, per the earlier ask) — no native low-effort case, since no
   sparse count format exists, but on the same primitive, ready for one.
-- `KmerPartition::query_partition_with` (`obikpartitionner/src/query_layer.rs`):
+- `KmerPartition::query_partition_with` (`obikpartition/src/query_layer.rs`):
   stage 2's column-major `for g { for slot { col_value } }` replaced by one
   `layer.nonzero_iter(&slot_list)` call per layer, format-agnostic.
 - Tests: `nonzero_iter_matches_dense`, `nonzero_iter_matches_row`, and —