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/implementation/partition_layer_cache.md

@@ -16,7 +16,7 @@ explicitly, since two of the names below are misleading.
   but it holds the *whole* multi-partition structure below — the name
   suggests "one partition", the value is all of them.
 - **Partition, the collection (not one partition)** =
-  `obikpartitionner::KmerPartition`. Despite the singular name, this owns
+  `obikpartition::KmerPartition`. Despite the singular name, this owns
   *every* partition of the index: `root_path`, `n_partitions`, and
   per-partition accessors that all take an explicit index `i`
   (`partition_dir(i)`, `index_dir(i)`, `layer_dir(i, l)`,
@@ -95,7 +95,7 @@ auto-detection" turns up three unrelated implementations:
 |---|---|---|---|
 | `Layer<D>` | `obilayeredmap` | one layer, `D` fixed at compile time | held alive by whoever owns the `Layer`, no policy of its own |
 | `Mat` | `obikphylo::siblings::cache` | one layer, format resolved per instance from an enum of 3 `Layer<D>` variants | yes, via `PartitionCache` |
-| `QueryLayer` | `obikpartitionner::query_layer` | one layer, `(MphfLayer, PersistentBitMatrix\|PersistentCompactIntMatrix)` pair, bypasses `Layer<D>` entirely | **no** — opened fresh inside `query_partition_with` on every call |
+| `QueryLayer` | `obikpartition::query_layer` | one layer, `(MphfLayer, PersistentBitMatrix\|PersistentCompactIntMatrix)` pair, bypasses `Layer<D>` entirely | **no** — opened fresh inside `query_partition_with` on every call |
 
 `query_partition_with` is `obikmer query`'s normal query path — the one
 most exposed to repeated cross-partition lookups — and it is the one with
@@ -164,7 +164,7 @@ Established in discussion, not yet coded:
   `open_data`/`layer_dir` — see git history around 2026-08-20). One
   `LayeredMap<D>` (or its heterogeneous-`D` successor) = one partition.
 - Nobody currently owns "the collection of partitions" as reusable state.
-  `obikpartitionner::KmerPartition` is the closest candidate — it already
+  `obikpartition::KmerPartition` is the closest candidate — it already
   owns `n_partitions()`/`part_dir(i)` — but today it is a pure
   config/path resolver, not a state holder: `dereplicate`, `count_kmer`,
   `obikindex`'s `distance.rs`/`stats.rs`, and
@@ -182,9 +182,9 @@ Established in discussion, not yet coded:
 2. A cache spanning multiple partitions, keeping (2)'s layer type open per
    partition per layer, for the whole lifetime of a long-running command —
    generalising `PartitionCache` minus its sibling-specific parts
-   (`fast_mode`, `find_presence_batch`) — living in `obikpartitionner`
+   (`fast_mode`, `find_presence_batch`) — living in `obikpartition`
    (owner of the partition dimension) and built on top of (1).
-3. `obikpartitionner::query_partition_with` — the normal query path,
+3. `obikpartition::query_partition_with` — the normal query path,
    currently uncached — becomes a consumer of (2), not just
    `obikphylo::PartitionCache`.
 
@@ -198,7 +198,7 @@ real number behind it for this codebase's scale).
 
 Groundwork for (1)/(2), landed ahead of the design itself:
 
-- `KmerPartition` (`obikpartitionner`) gained `partition_dir`/`index_dir`/
+- `KmerPartition` (`obikpartition`) gained `partition_dir`/`index_dir`/
   `layer_dir` as the single source of truth for a partition's on-disk
   layout, replacing per-module duplicated `const INDEX_SUBDIR: &str =
   "index"` (7 copies) and ad hoc path joins — including one found
@@ -266,7 +266,7 @@ storage decisions, now a *third* copy of the same logic to keep in sync)
   `Mat::open` already reads the result back in the sibling-annex path.
   Stale comment, not corrected.
 - **Retracted (2026-08-20)**: an earlier pass through this doc claimed
-  `obikpartitionner::query_layer::QueryLayer::open` had no sparse-format
+  `obikpartition::query_layer::QueryLayer::open` had no sparse-format
   detection and would silently corrupt reads on a `pack --sparse`d layer.
   False — `PersistentBitMatrix` (`obicompactvec::bitmatrix::persistent`)
   is a 4-way enum (`Columnar`/`Packed`/`Sparse`/`Implicit`), not 3-way as