docs: rename the native provider to @soulcraft/cor across public docs and JSDoc

The 3.0 native engine ships as @soulcraft/cor (brainy 8.x <-> cor 3.x are a
version-matched pair); the old @soulcraft/cortex package stays on the 2.x/7.x
line. Public docs and .d.ts-visible comments now name the correct package.
Historical 2.x contract references (e.g. the 2.3.1 read-side fallback) keep
the old name deliberately.

docs/guides/enterprise-for-everyone.md

@@ -174,13 +174,13 @@ await brain.syncWith({
 const brain = new Brainy()
 
 // 1 → ~1M vectors: pure-JS HNSW, zero extra setup
-// 1M → 10B+ vectors: install @soulcraft/cortex for the native DiskANN provider
+// 1M → 10B+ vectors: install @soulcraft/cor for the native DiskANN provider
 ```
 
 **Scaling model:**
 - **Single process, no cluster**: Brainy runs in one process — no coordinator,
   no peer discovery, no consensus to operate
-- **Optional native provider**: install `@soulcraft/cortex` to back the index with
+- **Optional native provider**: install `@soulcraft/cor` to back the index with
   on-disk DiskANN that scales to 10B+ vectors on one machine
 - **Per-tenant pools**: isolate tenants by giving each its own Brainy instance and
   storage directory