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/vfs/COMMON_PATTERNS.md

@@ -84,7 +84,7 @@ const brain = new Brainy({
 const brain = new Brainy({
   storage: {
     type: 'filesystem',
-    rootDirectory: '/var/lib/brainy'
+    path: '/var/lib/brainy'
   }
 })
 

docs/vfs/VFS_API_GUIDE.md

@@ -636,7 +636,7 @@ const brain = new Brainy({ storage: { type: 'memory' } })
 const brain = new Brainy({
   storage: {
     type: 'filesystem',
-    rootDirectory: './brainy-data'
+    path: './brainy-data'
   }
 })
 
@@ -644,7 +644,7 @@ const brain = new Brainy({
 const vfs = new VirtualFileSystem(brain)
 ```
 
-For off-site backup of the filesystem artifact, snapshot `rootDirectory` from your scheduler (`gsutil rsync`, `aws s3 sync`, `rclone`, `tar`).
+For off-site backup of the filesystem artifact, snapshot `path` from your scheduler (`gsutil rsync`, `aws s3 sync`, `rclone`, `tar`).
 
 **Custom Storage Adapters:** Redis, PostgreSQL, and other databases can be added via the [extension system](../api/EXTENSIBILITY.md). See `src/config/extensibleConfig.ts` for examples.
 

docs/vfs/VFS_GRAPH_TYPES.md

@@ -110,7 +110,8 @@ While using standard graph types, VFS adds domain-specific metadata for efficien
 ### 1. Cross-Domain Queries
 ```javascript
 // Find all documents (including VFS files) about "machine learning"
-const results = await brain.search('machine learning', {
+const results = await brain.find({
+  query: 'machine learning',
   where: { type: NounType.Document }
 })
 ```

docs/vfs/VFS_INITIALIZATION.md

@@ -149,7 +149,7 @@ API: a persisted snapshot contains every VFS file, and a snapshot opened
 with `Brainy.load()` serves VFS reads at the snapshot's state:
 
 ```javascript
-const brain = new Brainy({ storage: { type: 'filesystem', rootDirectory: './data' } })
+const brain = new Brainy({ storage: { type: 'filesystem', path: './data' } })
 await brain.init()
 
 // Create files