refactor(8.0)!: remove orphaned zero-config subsystem + dead cloud/progressive-init storage vestige

The old config-generation subsystem (src/config/ + autoConfiguration.ts) was
superseded during the 8.0 rework and never wired into init(): it emitted settings
for a partitioning subsystem that no longer exists and probed deleted cloud env
vars. The live zero-config path is inline — recall preset → HNSW knobs, storage
auto-detect, auto persistMode, container-memory-aware cache sizing.

The storage progressive-init / cloud-detection cluster was equally dead after the
cloud adapters were dropped: isCloudStorage() is permanently false (no overriders),
scheduleBackgroundInit/runBackgroundInit were never called (the latter an empty
body), initMode was never assigned, and Brainy.isFullyInitialized()/
awaitBackgroundInit() were always-trivial with zero callers. scheduleCountPersist()
collapses to its only-ever-taken immediate write-through path.

Removed:
- src/config/{index,zeroConfig,storageAutoConfig,modelAutoConfig,sharedConfigManager}.ts
- src/utils/autoConfiguration.ts + the inert BrainyZeroConfig export
- Brainy.isFullyInitialized()/awaitBackgroundInit() (+ BrainyInterface decls)
- InitMode type, isCloudStorage/detectCloudEnvironment/resolveInitMode,
  scheduleBackgroundInit/runBackgroundInit/ensureValidatedForWrite and their state
- Dead cloud env-var probes (K_SERVICE/K_REVISION/AWS_LAMBDA_FUNCTION_NAME/
  FUNCTIONS_TARGET/AZURE_FUNCTIONS_ENVIRONMENT)

Kept (verified live): production-detection logging (environment.ts), container-
memory cache sizing (memoryDetection/paramValidation), on-disk hash bucketing
(sharding.ts).

Docs: scrubbed deleted-subsystem references (JS quantization knobs, cloud/OPFS
adapters, partitioning, old zero-config API) across 14 files; deleted two wholly-
obsolete feature docs (complete-feature-list, v3-features); rewrote
architecture/zero-config for 8.0.

~3,700 LOC removed. Build clean; 1392 unit + 24 db-mvcc green.

docs/SCALING.md

@@ -35,10 +35,9 @@ Brainy 8.0 is a **single-node library**. There is no cluster, no peer discovery,
 The three knobs that matter most:
 
 1. **`config.vector.recall`** — `'fast'`, `'balanced'`, or `'accurate'` (default `'balanced'`)
-2. **`config.vector.quantization`** — `{ bits: 4 | 8 }` for memory savings on the open-core JS vector index
-3. **`config.vector.persistMode`** — `'immediate'` for durability, `'deferred'` for throughput
+2. **`config.vector.persistMode`** — `'immediate'` for durability, `'deferred'` for throughput
 
-The native vector provider (via the optional `@soulcraft/cortex` package) extends this with a higher-performing index when installed.
+The native vector provider (via the optional `@soulcraft/cortex` package) extends this with a higher-performing index — and its own at-scale acceleration such as on-disk compressed indexing — when installed.
 
 ## Storage Configurations
 
@@ -95,7 +94,6 @@ const brain = new Brainy({
   storage: { type: 'filesystem', rootDirectory: '/var/lib/brainy' },
   vector: {
     recall: 'fast',                // Trade recall for latency
-    quantization: { bits: 8 },     // SQ8 quantization
     persistMode: 'deferred'        // Batch persistence
   }
 })
@@ -142,8 +140,7 @@ Your service layer handles routing and isolation; Brainy stays simple.
 const brain = new Brainy({
   storage: { type: 'filesystem', rootDirectory: '/var/lib/brainy' },
   vector: {
-    recall: 'accurate',
-    quantization: { bits: 8 }
+    recall: 'accurate'
   }
 })
 ```
@@ -153,7 +150,6 @@ const brain = new Brainy({
 | Setting | Values | When to change |
 |---------|--------|----------------|
 | `vector.recall` | `'fast'` / `'balanced'` / `'accurate'` | Trade recall for latency |
-| `vector.quantization.bits` | `4` / `8` | Smaller index, lower memory |
 | `vector.persistMode` | `'immediate'` / `'deferred'` | Throughput vs. durability |
 | `storage.cache.maxSize` | integer | Hot-path read cache size |
 | `storage.cache.ttl` | ms | Cache freshness |
@@ -174,14 +170,13 @@ const stats = await brain.stats()
 
 ### Issue: Slow queries
 1. Switch to `vector.recall: 'fast'`
-2. Enable SQ8 quantization
-3. Increase the read cache (`storage.cache.maxSize`)
-4. Consider the optional native vector provider via `@soulcraft/cortex`
+2. Increase the read cache (`storage.cache.maxSize`)
+3. Consider the optional native vector provider via `@soulcraft/cortex`
 
 ### Issue: Memory pressure
-1. Enable `vector.quantization: { bits: 4 }` or `{ bits: 8 }`
-2. Reduce `storage.cache.maxSize`
-3. Move to `vector.persistMode: 'deferred'` to batch writes
+1. Reduce `storage.cache.maxSize`
+2. Move to `vector.persistMode: 'deferred'` to batch writes
+3. Consider the optional native vector provider via `@soulcraft/cortex` for at-scale index acceleration
 
 ### Issue: Slow startup after a crash
 1. Use `vector.persistMode: 'immediate'` so the index file stays in sync with storage
@@ -198,5 +193,5 @@ const stats = await brain.stats()
 
 - Brainy 8.0 is a **library**, not a cluster
 - Storage adapters: `filesystem`, `memory`, `auto`
-- Vector tuning: `recall`, `quantization`, `persistMode`
+- Vector tuning: `recall`, `persistMode`
 - Backup is an operator-layer concern — snapshot `rootDirectory`