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>

CONTRIBUTING.md

@@ -43,15 +43,38 @@ Feature requests are welcome! Please provide:
 
 #### Development Setup
 
+**Quick Setup (Recommended):**
 ```bash
 # Clone your fork
 git clone https://github.com/your-username/brainy.git
 cd brainy
 
-# Install dependencies
+# Run setup script (installs all dependencies including Rust)
+./scripts/setup-dev.sh
+```
+
+**Manual Setup:**
+```bash
+# Clone your fork
+git clone https://github.com/your-username/brainy.git
+cd brainy
+
+# Install system dependencies (Ubuntu/Debian)
+sudo apt-get install -y build-essential pkg-config libssl-dev
+
+# Install Rust (for WASM embedding engine)
+curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
+source ~/.cargo/env
+rustup target add wasm32-unknown-unknown
+cargo install wasm-pack
+
+# Install Node.js dependencies
 npm install
 
-# Build the project
+# Build Candle WASM embedding engine
+npm run build:candle
+
+# Build TypeScript
 npm run build
 
 # Run tests