Extend agent tests for cloud fleet features and erasure lanes.

Cover fleet torrent DHT fetch, cloud map/venue/meta IMDS mocks, S3 shard fetch order, zero-server policy polling, self-surgery reorder, contingency skip paths, epidemiology fix guards, and ssm_document deploy lane.

agent/deploy/cloud_map_test.go

@@ -41,3 +41,32 @@ func TestCloudMapEndpointUnset(t *testing.T) {
 		t.Fatalf("got=%q", got)
 	}
 }
+
+func TestCloudMapLANSeederHintsSkipsUnhealthy(t *testing.T) {
+	doc := CloudMapRegistryDocument{
+		Instances: []CloudMapRegistryInstance{
+			{AgentID: "good", IP: "10.0.1.5", FetchURL: "http://10.0.1.5/manifest", Healthy: true},
+			{AgentID: "bad", IP: "10.0.1.6", FetchURL: "http://10.0.1.6/manifest", Healthy: false},
+		},
+	}
+	hints := CloudMapLANSeederHints(doc)
+	if len(hints) != 1 || hints[0].AgentID != "good" {
+		t.Fatalf("hints=%+v", hints)
+	}
+}
+
+func TestSyncCloudMapRegistryMergesGossip(t *testing.T) {
+	SetCloudMapHTTPGetForTest(func(url string) ([]byte, error) {
+		return []byte(`{"instances":[{"agent_id":"seed-x","healthy":true,"fetch_url":"http://10.0.2.1/manifest","ip":"10.0.2.1"}]}`), nil
+	})
+	defer SetCloudMapHTTPGetForTest(nil)
+	var merged []FleetGossipRecord
+	if err := SyncCloudMapRegistry("http://registry.local/v1", func(recs []FleetGossipRecord) {
+		merged = append(merged, recs...)
+	}); err != nil {
+		t.Fatal(err)
+	}
+	if len(merged) != 1 || merged[0].TargetAgentID != "seed-x" {
+		t.Fatalf("merged=%+v", merged)
+	}
+}