Add autogroup:danger-all as a valid source alias that matches ALL IP
addresses including non-Tailscale addresses. When used as a source,
it resolves to 0.0.0.0/0 + ::/0 internally but produces SrcIPs: ["*"]
in filter rules. When used as a destination, it is rejected with an
error matching Tailscale SaaS behavior.
Key changes:
- Add AutoGroupDangerAll constant and validation
- Add sourcesHaveDangerAll() helper and hasDangerAll parameter to
srcIPsWithRoutes() across all compilation paths
- Add ErrAutogroupDangerAllDst for destination rejection
- Remove 3 AUTOGROUP_DANGER_ALL skip entries (K6, K7, K8)
Updates #2180
687cf0882f