fix(identity): ask the route question against a name that still answers

.changeset/stable-id-follows-the-relay.md

@@ -0,0 +1,5 @@
+---
+"ftw": patch
+---
+
+The stable software identity resolves again. It is anchored on the permanent MAC of whichever interface carries the box's uplink, and the question was asked against `uplink.home.sourceful.energy` — Home Link, retired in August 2026, DNS record and all — so every resolution died at the lookup before a route was ever read. The question now goes to `relay.ftw.energy`, which the box dials anyway. The MAC is the identity and the host never was, so the same box derives the same identity over the live name.

go/internal/gatewayidentity/stableid.go

@@ -10,7 +10,14 @@ import (
 )
 
 const (
-	SoftwareIdentityUplinkHost = "uplink.home.sourceful.energy"
+	// The host is only a question to the kernel — "which interface would
+	// carry my uplink?" — so it must be a name the box actually dials.
+	// It was uplink.home.sourceful.energy until Home Link was retired
+	// (Aug 2026) and its DNS record with it; a dead name here made every
+	// identity resolution fail on the lookup, before any route was read.
+	// The MAC of the answering interface is the identity; the host never
+	// is, so this change re-derives the same identity over a live name.
+	SoftwareIdentityUplinkHost = "relay.ftw.energy"
 	SoftwareIdentityUplinkPort = 443
 )
 

go/internal/gatewayidentity/stableid_test.go

@@ -56,7 +56,7 @@ func mustMAC(raw string) net.HardwareAddr {
 }
 
 func TestStableInterfaceUsesKernelResolvedOutputForEveryAddress(t *testing.T) {
-	if SoftwareIdentityUplinkHost != "uplink.home.sourceful.energy" {
+	if SoftwareIdentityUplinkHost != "relay.ftw.energy" {
 		t.Fatalf("software identity uplink = %q", SoftwareIdentityUplinkHost)
 	}
 	authority := &fakeRouteAuthority{