Add routable_ips and approved_routes fields to the node topology
definitions in all golden test files. These represent the subnet
routes actually advertised by nodes on the Tailscale SaaS network
during data capture:
Routes topology (92 files, 6 router nodes):
big-router: 10.0.0.0/8
subnet-router: 10.33.0.0/16
ha-router1: 192.168.1.0/24
ha-router2: 192.168.1.0/24
multi-router: 172.16.0.0/24
exit-node: 0.0.0.0/0, ::/0
ACL topology (199 files, 1 router node):
subnet-router: 10.33.0.0/16
Grants topology (203 files, 1 router node):
subnet-router: 10.33.0.0/16
The route assignments were deduced from the golden data by analyzing
which router nodes receive FilterRules for which destination CIDRs
across all test files, and cross-referenced with the MTS setup
script (setup_grant_nodes.sh).
Updates #2180
Replace 9,937 lines of inline Go test expectations with 215 JSON golden files captured from Tailscale SaaS. The new data-driven test driver compares headscale's filter compilation output against real Tailscale behavior for each node in an 8-node topology.
Updates #2180
