feat: introduce layered MPHF indexing and partition metadata

Refactors obikindex and obikpartitionner to delegate index construction to a new layered MPHF implementation. Adds resume-safe building with abundance filtering and count persistence, while introducing a PartitionMeta struct for JSON configuration persistence. Updates OKIError to wrap layer-specific errors, replaces single-path extraction with full path collection and logging, and registers new internal dependencies across the workspace.

src/Cargo.lock

@@ -1452,17 +1452,10 @@ dependencies = [
 name = "obikindex"
 version = "0.1.0"
 dependencies = [
- "cacheline-ef",
- "epserde",
  "indicatif",
- "obicompactvec",
- "obidebruinj",
  "obikpartitionner",
- "obikseq",
- "obilayeredmap",
  "obiskio",
  "obisys",
- "ptr_hash",
  "rayon",
  "serde",
  "serde_json",
@@ -1501,8 +1494,10 @@ dependencies = [
  "memmap2",
  "niffler 3.0.0",
  "obicompactvec",
+ "obidebruinj",
  "obikrope",
  "obikseq",
+ "obilayeredmap",
  "obiread",
  "obiskbuilder",
  "obiskio",