feat: migrate embeddings to Candle WASM + remove semantic type inference

Major architectural changes:

1. EMBEDDINGS ENGINE (ONNX → Candle WASM):
   - Replace ONNX Runtime with Rust Candle compiled to WASM
   - Embedded model in WASM binary (no external downloads)
   - Quantized Q8 precision with <50MB memory footprint
   - Zero-download, offline-first operation
   - Same embedding quality (all-MiniLM-L6-v2)

2. REMOVE SEMANTIC TYPE INFERENCE:
   - Delete embeddedKeywordEmbeddings.ts (14MB of pre-computed embeddings)
   - Remove typeAwareQueryPlanner.ts and semanticTypeInference.ts
   - Remove VerbExactMatchSignal (uses keyword embeddings)
   - Update SmartRelationshipExtractor to 3 signals (55%/30%/15% weights)

API CHANGES (requires v7.0.0):
- Removed: inferTypes(), inferNouns(), inferVerbs(), inferIntent()
- Removed: getSemanticTypeInference(), SemanticTypeInference class
- Removed: TypeInference, SemanticTypeInferenceOptions types

Users can still use natural language queries in find() - they just
need to specify type explicitly for type-optimized searches.

PACKAGE SIZE IMPACT:
- Compressed: 90.1 MB → 86.2 MB (-4.3%)
- Uncompressed: 114.4 MB → 100.3 MB (-12%)
- ~448K lines of code removed

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/embeddings/EmbeddingManager.ts

@@ -2,11 +2,11 @@
  * Unified Embedding Manager
  *
  * THE single source of truth for all embedding operations in Brainy.
- * Uses direct ONNX WASM inference for universal compatibility.
+ * Uses Candle WASM inference for universal compatibility.
  *
  * Features:
  * - Singleton pattern ensures ONE model instance
- * - Direct ONNX WASM (no transformers.js dependency)
+ * - Candle WASM (no transformers.js or ONNX Runtime dependency)
  * - Bundled model (no runtime downloads)
  * - Works everywhere: Node.js, Bun, Bun --compile, browsers
  * - Memory monitoring
@@ -34,7 +34,7 @@ let globalInitPromise: Promise<void> | null = null
 /**
  * Unified Embedding Manager - Clean, simple, reliable
  *
- * Now powered by direct ONNX WASM for universal compatibility.
+ * Now powered by Candle WASM for universal compatibility.
  */
 export class EmbeddingManager {
   private engine: WASMEmbeddingEngine