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/augmentations/README.md

@@ -55,10 +55,11 @@ Replace or enhance the storage layer.
 
 | Augmentation | Description | Timing | Status |
 |-------------|-------------|--------|--------|
-| **S3StorageAugmentation** | Use S3 as storage backend | `replace` | 📝 Example |
 | **RedisAugmentation** | Redis caching layer | `around` | 📝 Example |
 | **PostgresAugmentation** | PostgreSQL persistence | `replace` | 📝 Example |
 
+> Brainy 8.0 ships `filesystem` and `memory` adapters out of the box. For off-site backup of the filesystem artifact, snapshot `rootDirectory` from your scheduler (`gsutil rsync`, `aws s3 sync`, `rclone`, `tar`).
+
 ### 🔄 Real-time & Sync
 Handle real-time updates and synchronization.
 
@@ -73,7 +74,6 @@ Core infrastructure and reliability features.
 
 | Augmentation | Description | Timing | Status |
 |-------------|-------------|--------|--------|
-| **ConnectionPoolAugmentation** | Optimize cloud storage connections | `before` | ✅ Production |
 | **RequestDeduplicatorAugmentation** | Prevent duplicate concurrent requests | `before` | ✅ Production |
 | **TransactionAugmentation** | ACID transaction support | `around` | 🚧 Planned |
 | **CacheAugmentation** | Multi-level caching | `around` | ✅ Production |