Ban lists: where Guard and fail2ban ban addresses

A program bans an address (every port, or a protocol's ports) for a
time; the ban list says what it is kept from: the firewall, some hosts
behind it, or everything. Bans drop ahead of every rule, close the
address's connections, group IPv6 by /64, are kept in the database
across restarts and audited. Never banned: the inside, the firewall's
own addresses, the caller, the list's never. bans grant (bans:write:LIST),
hc banlist/bans/ban/unban, Traffic -> Bans, a fail2ban action in contrib/,
and failed logins and refused tokens logged for Guard and fail2ban.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/engine/engine.go

@@ -509,6 +509,12 @@ func Normalize(st *model.State) {
 		normMatch(&x.Match)
 		x.ToPort = normPorts(x.ToPort)
 	}
+	for _, b := range st.BanLists {
+		b.Name = strings.TrimSpace(b.Name)
+		b.Scope = strings.ToLower(strings.TrimSpace(b.Scope))
+		b.Hosts = normAddrs(b.Hosts)
+		b.Never = normAddrs(b.Never)
+	}
 	// Positions are fractions after insertions between rules; renumber
 	// only when two have come too close to put another between.
 	st.Sort()