feat: Add vis.js graph visualization examples

Added interactive visualization capabilities with vis.js:

New Files:
- examples/visualization-browser.html (15KB) - Standalone interactive demo
  - 4 pre-loaded example datasets (job search, social, knowledge, dependencies)
  - Color-coded node types with hover details
  - Interactive controls: zoom, pan, reset view
  - Real-time graph statistics panel
  - No backend required - runs entirely in browser

- examples/visualization-export.ts (204 lines) - Export to vis.js format
  - Convert sqlite-graph data to vis.js JSON format
  - Generate standalone HTML visualizations
  - Export raw JSON for custom visualizations
  - Job search graph example with 11 nodes, 14 edges
  - Demonstrates graph traversal queries for filtering

Dependencies:
- [email protected] (dev dependency)
- [email protected] (dev dependency)

Use Cases:
- Visual debugging of graph structures
- Interactive exploration of relationships
- Demo and presentation tool
- Export data for external visualization tools

Run Examples:
```bash
# Generate visualization from graph data
npx ts-node examples/visualization-export.ts

# Open in browser
open examples/job-search-visualization.html
open examples/visualization-browser.html
```

Features:
✅ Interactive node dragging and zooming
✅ Automatic graph layout with physics simulation
✅ Color-coded node types
✅ Edge labels showing relationship types
✅ Click nodes to see properties
✅ Export to JSON for custom tools
✅ Standalone HTML (no server needed)

🚀 Generated with Claude Code
Co-Authored-By: Claude <[email protected]>

Author: michaeloboyle

examples/.gitignore

@@ -0,0 +1,2 @@
+*.html
+*.json