feat(8.0): brain.fillSubtypes migration helper + pre-RC1 gap closure

- brain.fillSubtypes(rules): idempotent subtype back-fill for pre-8.0 data.
  One rule per NounType/VerbType (literal default or per-entry function);
  fills only entries still missing a subtype through the public update()/
  updateRelation() paths; returns { scanned, filled, skipped, errors, byType }.
  Full unit suite in tests/unit/brainy/fill-subtypes.test.ts.
- Fix getNouns/getVerbs pagination hasMore (peek one past the window) —
  was permanently false, silently truncating every multi-page walk.
- find({ near }) without near.id now throws a teaching error instead of an
  opaque storage sharding failure; CLI --threshold without --near applies a
  plain score floor.
- CLI init/close audit: every one-shot command init()s, close()s, and exits
  explicitly; delete the unmaintained interactive REPL; replace the cloud-era
  storage subcommands with status/batch-delete; new types/validate commands.
- requireSubtype JSDoc now documents the 8.0 default-on contract; audit()
  recommendation points at fillSubtypes.
- Docs: data-storage-architecture rewritten to the real 8.0 on-disk layout;
  README storage section reflects filesystem+memory and snapshots; eli5 and
  SEMANTIC_VFS /as-of/ semantics corrected; internal tracker IDs and
  .strategy references scrubbed from published files.

src/storage/storageFactory.ts

@@ -8,7 +8,7 @@
  *   workloads.
  *
  * Cloud-storage adapters (GCS, S3, R2, Azure) and the browser-only OPFS
- * adapter were removed in 8.0 per `BR-BRAINY-80-STORAGE-SIMPLIFY`. The path
+ * adapter were removed in 8.0. The path
  * forward for cloud backup is operator tooling: persist locally with
  * `db.persist()`, sync the resulting on-disk artefact with `gsutil` /
  * `aws s3 cp` / `rclone` / `azcopy`. This is the standard pattern every