docs(8.0): Phase F — deep clean across 21 docs

Aligned every public doc to the 8.0 contract: filesystem + memory adapters
only, vector index provider terminology (config.vector with recall +
quantization + persistMode knobs), no cloud storage adapters, no closed-
source product names.

Tier 1 — heavier rewrites:
- docs/architecture/storage-architecture.md
- docs/architecture/data-storage-architecture.md
- docs/architecture/distributed-storage.md DELETED — content was 100%
  cloud-coordination examples with no 8.0 substance.
- docs/guides/distributed-system.md DELETED — same reason; no inbound refs.
- docs/SCALING.md rewritten for single-node guidance.
- docs/PLUGINS.md, docs/augmentations/{COMPLETE-REFERENCE,README}.md:
  HnswProvider→VectorIndexProvider, hnsw→vector key.
- docs/PERFORMANCE.md, docs/BATCHING.md cloud-detection + sharding
  sections replaced with single-node vector tuning + filesystem framing.

Tier 2 — surgical renames + cloud-section deletions:
- architecture/{index,initialization-and-rebuild,overview}.md
- transactions.md, DEVELOPER_LEARNING_PATH.md
- vfs/{VFS_API_GUIDE,COMMON_PATTERNS}.md
- api/README.md, guides/{inspection,import-flow}.md

Tier 3 — light edits:
- docs/README.md, architecture/augmentation-system-audit.md

MIGRATION-V3-TO-V4.md untouched (internal migration doc, no stale terms).

docs/vfs/VFS_API_GUIDE.md

@@ -632,60 +632,20 @@ VFS works with all built-in Brainy storage adapters:
 // Memory (testing/development)
 const brain = new Brainy({ storage: { type: 'memory' } })
 
-// Filesystem (local development)
+// Filesystem (production default)
 const brain = new Brainy({
   storage: {
     type: 'filesystem',
-    path: './brainy-data'
+    rootDirectory: './brainy-data'
   }
 })
 
-// S3-compatible storage (production)
-const brain = new Brainy({
-  storage: {
-    type: 's3',
-    bucket: 'my-bucket',
-    region: 'us-east-1'
-  }
-})
-
-// Cloudflare R2 (production)
-const brain = new Brainy({
-  storage: {
-    type: 'r2',
-    accountId: 'your-account-id',
-    bucket: 'my-bucket'
-  }
-})
-
-// Google Cloud Storage (production)
-const brain = new Brainy({
-  storage: {
-    type: 'gcs',
-    bucket: 'my-bucket',
-    projectId: 'my-project'
-  }
-})
-
-// Azure Blob Storage (production)
-const brain = new Brainy({
-  storage: {
-    type: 'azure',
-    accountName: 'myaccount',
-    containerName: 'my-container'
-  }
-})
-
-// OPFS (browser-native persistence)
-const brain = new Brainy({ storage: { type: 'opfs' } })
-
-// TypeAware storage (optimized for entity types)
-const brain = new Brainy({ storage: { type: 'typeaware' } })
-
-// All work identically with VFS
+// Both work identically with VFS
 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`).
+
 **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.
 
 ### Best Practices