🚀 Camoufox default web engine — auto-install + auto-start

Full integration:
- install.sh now installs camoufox-browser via npm (preferred) or Docker
- install.sh creates systemd/launchd auto-start service on Linux/macOS
- New browser_manager.rs — health-check, auto-start, wait-for-ready
- AgentLoop::run() auto-inits Camoufox and registers web_search/web_browse
- System prompt tells LLM to use web_search/web_browse as PRIMARY tools
- Graceful fallback: if Camoufox unavailable, logs warning, uses bash tools
- ToolExecutor is now Arc<Mutex<>> for runtime tool registration

GyanDoot v2 now: install → Camoufox auto-starts → web tools available →
"search NSE India" uses Camoufox with anti-detection 🎯

Cargo.lock

@@ -675,6 +675,7 @@ dependencies = [
  "anyhow",
  "async-trait",
  "chrono",
+ "dirs",
  "gyandoot-browser",
  "gyandoot-core",
  "gyandoot-memory",