feat: Embedded local worker for offline/local mode (v0.3.4)

Implement inline worker creation using embedded worker bundle:
- Add separate webpack configs for worker and main bundles
- Worker is built first, then embedded as base64 in TypeScript
- WorkerWrapper creates inline worker via Blob URL when URL not provided
- Version number now injected at build time from package.json

This enables ai-delegate to work without requiring a separate worker
file to be served, useful for offline/local development scenarios.

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