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/architecture/triple-intelligence.md

@@ -68,7 +68,7 @@ const articles = await brain.find("verified articles by John Smith about machine
 
 #### Simple Vector Search
 ```typescript
-const results = await brain.search("machine learning concepts")
+const results = await brain.find("machine learning concepts")
 ```
 
 #### Combined Intelligence Query
@@ -161,7 +161,7 @@ Brainy includes 220+ embedded patterns for natural language understanding:
 
 ```typescript
 // Natural language automatically parsed
-const results = await brain.search(
+const results = await brain.find(
   "show me recent AI papers from Stanford published this year"
 )
 // Automatically converts to:
@@ -189,10 +189,10 @@ The NLP processor identifies query intent:
 Successful execution plans are cached:
 ```typescript
 // First query: 50ms (plan generation + execution)
-await brain.search("machine learning papers")
+await brain.find("machine learning papers")
 
 // Subsequent similar queries: 10ms (cached plan)
-await brain.search("deep learning papers")
+await brain.find("deep learning papers")
 ```
 
 ### Self-Optimization