* feat(tailscale): add Tailscale control center widget
Full-stack Tailscale integration for DMS control center:
Backend (Go):
- Event-driven manager via WatchIPNBus (no polling)
- Reconnects with exponential backoff when tailscaled unavailable
- Typed conversion from ipnstate.Status to QML-friendly IPC types
- Testable via tailscaleClient interface with mock watcher
- Manager cleanup in cleanupManagers()
- 19 unit tests
Frontend (QML):
- TailscaleService with WebSocket subscription
- TailscaleWidget with peer list, filter chips, search
- Copy-to-clipboard for IPs and DNS names
- Daemon lifecycle handling (offline/stopped states)
Dependencies:
- Add tailscale.com v1.96.1 (official local API client)
- Bump Go to 1.26.1 (required by tailscale.com)
* cleanups
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Co-authored-by: bbedward <bbedward@gmail.com>
