According to Tailscale SaaS behavior, autogroup:internet is handled
by exit node routing via AllowedIPs, not by packet filtering. ACL
rules with autogroup:internet as destination should produce no
filter rules for any node.
Previously, Headscale expanded autogroup:internet to public CIDR
ranges and distributed filters to exit nodes (because 0.0.0.0/0
"covers" internet destinations). This was incorrect.
Add detection for AutoGroupInternet in filter compilation to skip
filter generation for this autogroup. Update test expectations
accordingly.
Fix two compatibility issues discovered in Tailscale SaaS testing:
1. Wildcard DstPorts format: Headscale was expanding wildcard
destinations to CGNAT ranges (100.64.0.0/10, fd7a:115c:a1e0::/48)
while Tailscale uses {IP: "*"} directly. Add detection for
wildcard (Asterix) alias type in filter compilation to use the
correct format.
2. proto:icmp handling: The "icmp" protocol name was returning both
ICMPv4 (1) and ICMPv6 (58), but Tailscale only returns ICMPv4.
Users should use "ipv6-icmp" or protocol number 58 explicitly
for IPv6 ICMP.
Update all test expectations accordingly. This significantly reduces
test file line count by replacing duplicated CGNAT range patterns
with single wildcard entries.
