feat(8.0): API simplification — remove neural()/Db.search, one storage path key, integration→0

8.0 RC cleanup toward "one place per thing, zero-config, no deprecation":

- Remove the `brain.neural()` clustering namespace (ImprovedNeuralAPI + the dead
  legacy NeuralAPI + the neural CLI + neural-only types). Similarity is `find({vector})`
  / `similar({to})`; attribute grouping is the aggregation `GROUP BY` engine. The separate
  entity-extraction / smart-import feature (NeuralImport, NeuralEntityExtractor, SmartExtractor,
  NaturalLanguageProcessor, `brain.extract()`/`brain.nlp()`) is kept.
- Remove `Db.search()`; `find()` is the one query verb (accepts a bare string or FindParams).
  Fix the bundled MCP client, which called a non-existent `brain.search(query, limit)` →
  now `find({ query, limit })`.
- Storage config: collapse to one canonical top-level `path` key. The pre-8.0 aliases
  (`rootDirectory`, `options.*`, `fileSystemStorage.*`) are removed and now THROW with the
  exact rename instead of silently defaulting to `./brainy-data` on upgrade. A single resolver
  feeds createStorage, the 7.x→8.0 migration probe, and the plugin-factory handoff, so a native
  storage provider resolves the identical root (no split-brain).
- Fix `similar({ threshold })`: the min-similarity filter was silently dropped; it is now
  applied as a post-filter on `result.score` (the documented way to bound semantic results).
- Fix `vfs.rename()` on a directory: child path updates spread the entity vector into `update()`
  and failed dimension validation; they are metadata-only updates now.
- Fix `vfs.move()`: copy+delete orphaned the content-addressed content blob (the destination
  shared the source hash, then unlink removed it). `move()` now delegates to `rename()` — an
  in-place path change that preserves the blob and the entity id, for files and directories.
- Fix streaming import: the bulk fast path never flushed mid-import nor signalled queryability.
  Entity writes are now chunked by a progressive flush interval (100 → 1000 → 5000); each chunk
  flushes and emits `progress.queryable`, so imported data is queryable during the import.
- Sweep all docs, comments, and JSDoc for the removed/changed APIs.

Integration suite: 49 files / 588 passed / 0 failed. Unit: 80 files / 1456 passed, no type errors.

docs/guides/storage-adapters.md

@@ -32,7 +32,7 @@ import { Brainy } from '@soulcraft/brainy'
 
 // Filesystem (recommended for any persistent workload):
 const brain = new Brainy({
-  storage: { type: 'filesystem', rootDirectory: './brainy-data' }
+  storage: { type: 'filesystem', path: './brainy-data' }
 })
 
 // Memory (tests, ephemeral):
@@ -102,20 +102,33 @@ Brainy 8.0 is smaller, faster to install, and clearer about what it does.
 // BrainyConfig['storage'] — either a config object or a pre-constructed adapter:
 storage?:
   | {
-      // The adapter type. Defaults to 'auto'
+      // The adapter type. Optional — a top-level `path` implies 'filesystem',
+      // so { path: '/data' } works without it. Defaults to 'auto'
       // (filesystem on Node-like runtimes, memory otherwise).
-      type: 'auto' | 'memory' | 'filesystem'
+      type?: 'auto' | 'memory' | 'filesystem'
 
-      // Root directory for filesystem storage. Passed through to storage
-      // factories, including plugin-provided ones.
+      // CANONICAL directory for filesystem storage. The rest of the API already
+      // speaks `path` (persist(path), Brainy.load(path), asOf(path),
+      // restore(path)). Specifying it implies type: 'filesystem'. Passed through
+      // to storage factories, including plugin-provided ones.
+      path?: string
+
+      // REMOVED in 8.0 — passing `rootDirectory` THROWS. Use `path`.
       rootDirectory?: string
 
-      // Adapter-specific options.
+      // REMOVED in 8.0 — a nested `options.{path,rootDirectory}` THROWS. Use `path`.
       options?: any
     }
   | StorageAdapter   // e.g. storage: new MemoryStorage()
 ```
 
+The canonical — and only — key is the top-level **`path`**. The pre-8.0 aliases
+`rootDirectory`, `options.{path,rootDirectory}`, and
+`fileSystemStorage.{path,rootDirectory}` were **removed in 8.0**: passing one now
+throws with the exact rename (never a silent default that would misplace data on
+upgrade). Because `path` implies filesystem, `{ path: '/data' }` is a complete
+config; the `type` is optional.
+
 ## Direct construction
 
 If you want to skip the factory:
@@ -138,7 +151,7 @@ backup tooling. The recipe:
 1. On the host running Brainy, mount a local disk (NVMe recommended). Cloud
    providers all expose persistent local disks: GCP Persistent Disk, AWS EBS,
    Azure Managed Disks.
-2. Set `storage: { type: 'filesystem', rootDirectory: '/mnt/brainy-data' }`.
+2. Set `storage: { type: 'filesystem', path: '/mnt/brainy-data' }`.
 3. Run your existing data import once into the new local store.
 4. Set up an operator backup job using `gsutil` / `aws s3` / `rclone` /
    `azcopy` on a cron — hourly or whatever your RPO requires. Point it at