Add an integration test that runs the tailscale-rs axum example
against headscale end-to-end. The test provisions one headscale
instance, one Go tailscale probe client (tsic), and one
tailscale-rs node (tsric) on the same tailnet, then verifies:
- the tailscale-rs node registers and is assigned both an IPv4
and an IPv6 address
- the Go probe sees the tailscale-rs node as a peer in its status
- GET /index.html and GET /assets/index.css from the axum server
return the expected content over the tailnet
- three sequential POST /count calls return distinct, incrementing
counter values, proving netstack state is maintained across
multiple TCP connections
This is the first integration test that exercises a non-Go
Tailscale client against headscale, giving end-to-end coverage of
the control protocol for alternate implementations.
