refactor: remove augmentation system and semantic type matching

Remove the entire augmentation pipeline infrastructure (52 files,
~15,000 lines) and the semantic type matching system. These were
unused middleware layers adding complexity without value.

What was removed:
- src/augmentations/ directory (all augmentation implementations)
- src/augmentationManager.ts (pipeline orchestrator)
- src/types/augmentations.ts, src/types/pipelineTypes.ts
- src/shared/default-augmentations.ts
- Semantic type suggestion (BrainyTypes.suggestNoun/suggestVerb)
- src/utils/typeMatching/ (embedding-based type matcher)

What was preserved by relocating:
- Import handlers (CSV, PDF, Excel) -> src/importers/handlers/
- NeuralImportAugmentation -> src/cortex/neuralImportAugmentation.ts
- Type matching utilities -> heuristic inference in consumers

What was simplified:
- brainy.ts: operations call storage directly (no execute() wrapper)
- IntegrationBase: standalone class (no BaseAugmentation parent)
- BrainyTypes: validation-only (nouns, verbs, isValid*, get*)
- Pipeline: direct execution (no augmentation interception)
- index.ts: removed TypeSuggestion, suggestType exports
- package.json: removed stale types/augmentations export

Build passes, 1176 tests pass, 0 failures.

tests/benchmarks/performance-v3.js

@@ -17,7 +17,6 @@ async function benchmarkV2() {
   
   const brain = new Brainy({
     storage: { type: 'memory' },
-    augmentations: false,
     embeddingFunction: async () => new Array(384).fill(0).map(() => Math.random())
   })
   await brain.init()
@@ -92,7 +91,6 @@ async function benchmarkV3() {
   
   const brain = new Brainy({
     storage: { type: 'memory' },
-    augmentations: {},
     warmup: false,
     embedder: async () => new Array(384).fill(0).map(() => Math.random())
   })