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/guides/import-flow.md

@@ -1687,11 +1687,11 @@ verbCounts['CreatedBy']
 
 ---
 
-### 8. Storage by Cloud Provider
+### 8. Storage Layout
 
-Brainy supports multiple storage adapters:
+Brainy 8.0 ships two adapters: filesystem and memory.
 
-#### File System (Local)
+#### Filesystem (Default)
 ```
 .brainy/
 ├── nouns/
@@ -1701,43 +1701,18 @@ Brainy supports multiple storage adapters:
 └── index.json
 ```
 
-#### Google Cloud Storage (GCS)
-```
-gs://my-bucket/brainy/
-├── nouns/
-│   └── ent_mona_lisa_1730000000000.json
-├── nouns-metadata/
-│   └── ent_mona_lisa_1730000000000.json
-└── ...
-```
-
-#### Amazon S3
-```
-s3://my-bucket/brainy/
-├── nouns/
-│   └── ent_mona_lisa_1730000000000.json
-└── ...
-```
-
-#### Cloudflare R2
-```
-r2://my-bucket/brainy/
-├── nouns/
-│   └── ent_mona_lisa_1730000000000.json
-└── ...
-```
-
 **Configuration**:
 ```typescript
 const brain = await Brainy.create({
   storage: {
-    type: 'gcs',
-    bucket: 'my-bucket',
-    prefix: 'brainy/'
+    type: 'filesystem',
+    rootDirectory: './.brainy'
   }
 })
 ```
 
+For off-site backup, snapshot `rootDirectory` from your scheduler with `gsutil rsync`, `aws s3 sync`, `rclone`, or `tar`. Brainy itself doesn't reach out to object storage.
+
 ---
 
 ## Performance & Scale