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/COMMON_PATTERNS.md

@@ -80,17 +80,16 @@ const brain = new Brainy({
   }
 })
 
-// ✅ Pattern 2: Cloud storage (production)
+// ✅ Pattern 2: Filesystem (production default)
 const brain = new Brainy({
   storage: {
-    type: 's3',
-    bucket: 'my-vfs-data',
-    region: 'us-west-2'
+    type: 'filesystem',
+    rootDirectory: '/var/lib/brainy'
   }
 })
 
 // ✅ Pattern 3: Auto-detection (recommended)
-const brain = new Brainy()  // Automatically chooses best storage
+const brain = new Brainy()  // Picks filesystem on Node, memory in browser
 ```
 
 ## 🔍 Search Patterns
@@ -563,7 +562,7 @@ function vfsMiddleware() {
 | ❌ **Avoid These Patterns** | ✅ **Use These Instead** |
 |---------------------------|------------------------|
 | Manual tree filtering | `vfs.getDirectChildren()` |
-| Memory storage for files | Filesystem or cloud storage |
+| Memory storage for files | Filesystem (snapshot off-site for backup) |
 | Sequential file operations | Parallel processing with limits |
 | Manual relationship tracking | Built-in `vfs.addRelationship()` |
 | Loading entire directories | Paginated/lazy loading |