refactor: remove src/cortex/ directory and fix README claims

- Move neuralImport.ts and neuralImportAugmentation.ts to src/neural/
- Delete 3 dead files (healthCheck, backupRestore, performanceMonitor)
- Remove cortex entries from package.json browser field
- Fix unsubstantiated performance claims in README (add PROJECTED labels)
- Delete stale dist/cortex/ artifacts

src/api/UniversalImportAPI.ts

@@ -16,7 +16,7 @@ import { NounType, VerbType } from '../types/graphTypes.js'
 import { Vector } from '../coreTypes.js'
 import type { Brainy } from '../brainy.js'
 import type { Entity, Relation } from '../types/brainy.types.js'
-import { NeuralImportAugmentation } from '../cortex/neuralImportAugmentation.js'
+import { NeuralImportAugmentation } from '../neural/neuralImportAugmentation.js'
 import { mimeDetector } from '../vfs/MimeTypeDetector.js'
 
 export interface ImportSource {