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.

src/types/brainy.types.ts

@@ -1282,14 +1282,37 @@ export interface BrainyConfig {
    */
   storage?:
     | {
-        type: 'auto' | 'memory' | 'filesystem'
-        /** Root directory for filesystem storage. Passed through to storage factories
-         *  including plugin-provided factories (e.g. native mmap providers). */
-        rootDirectory?: string
-        /** Alias for `rootDirectory`. The `storage: { type: 'filesystem', path: '…' }`
-         *  shape is honored as a first-class key so existing configs keep working. */
+        /**
+         * Storage backend. Optional — a top-level `path` implies `'filesystem'`,
+         * so `storage: { path: '/data' }` works without it. `'auto'` (the
+         * default) picks filesystem on Node, memory in a browser.
+         */
+        type?: 'auto' | 'memory' | 'filesystem'
+        /**
+         * **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 plugin-provided storage
+         * factories (e.g. native mmap providers) so they resolve the same root.
+         * @example
+         * new Brainy({ storage: { path: '/var/lib/app/data' } })
+         */
         path?: string
+        /**
+         * @deprecated REMOVED in 8.0 — passing `rootDirectory` THROWS. Use the
+         * canonical {@link path}.
+         */
+        rootDirectory?: string
+        /**
+         * @deprecated REMOVED in 8.0 — a nested `options.path` / `options.rootDirectory`
+         * THROWS. Use the top-level {@link path}.
+         */
         options?: any
+        /**
+         * @deprecated REMOVED in 8.0 — `fileSystemStorage.path` / `.rootDirectory`
+         * THROWS. Use the top-level {@link path}.
+         */
+        fileSystemStorage?: { path?: string; rootDirectory?: string; [key: string]: any }
       }
     | StorageAdapter