Add Cloud Map seeder discovery with VPC Lattice operator templates.

Agents poll AETHERFORGE_CLOUD_MAP_ENDPOINT to sync know_node gossip; deploy plans attach route_via DNS hints for standalone operator registries.

server/internal/api/deploy_plan_cloudmap_test.go

@@ -0,0 +1,42 @@
+package api
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"crypto-miner-server/internal/spreadrouter"
+)
+
+func TestAttachCloudMapRouteVia(t *testing.T) {
+	dir := t.TempDir()
+	cfg := map[string]interface{}{
+		"server": map[string]interface{}{
+			"cloud_map_namespace": "prod.local",
+			"cloud_map_service":   "seeder",
+		},
+	}
+	data, _ := json.Marshal(cfg)
+	if err := os.WriteFile(filepath.Join(dir, "config.json"), data, 0o644); err != nil {
+		t.Fatal(err)
+	}
+	h := &DeployPlanHandler{dataDir: dir}
+	body := DeployPlanBody{}
+	h.attachCloudMapRouteVia(&body)
+	if body.SpreadRouteHint == nil || body.SpreadRouteHint.RouteVia != "seeder.svc.prod.local" {
+		t.Fatalf("hint=%+v", body.SpreadRouteHint)
+	}
+}
+
+func TestAttachCloudMapRouteViaPreservesExisting(t *testing.T) {
+	dir := t.TempDir()
+	h := &DeployPlanHandler{dataDir: dir}
+	body := DeployPlanBody{
+		SpreadRouteHint: &spreadrouter.SpreadRouteHint{RouteVia: "custom.svc.lab.local"},
+	}
+	h.attachCloudMapRouteVia(&body)
+	if body.SpreadRouteHint.RouteVia != "custom.svc.lab.local" {
+		t.Fatalf("route_via=%q", body.SpreadRouteHint.RouteVia)
+	}
+}