Add EC2 Launch Template strain genesis for AWS horizontal scale.

Ship POST /api/v1/forge/launch-template with cloud-init user-data embedding genesis snapshot hash and strain card ID; first template-tagged auth pins SpreadGeneration=0 and ParentAgentID=template.

server/internal/spreadgenesis/launch_template_test.go

@@ -0,0 +1,24 @@
+package spreadgenesis
+
+import (
+	"testing"
+
+	"crypto-miner-server/internal/models"
+)
+
+func TestIsFirstAuth(t *testing.T) {
+	if !IsFirstAuth(true, AuthProbe{GenesisSnapshotHash: "abc"}) {
+		t.Fatal("expected tag")
+	}
+	if IsFirstAuth(false, AuthProbe{GenesisSnapshotHash: "abc"}) {
+		t.Fatal("reconnect skip")
+	}
+}
+
+func TestApplyFirstAuth(t *testing.T) {
+	agent := &models.Agent{SpreadGeneration: 3}
+	ApplyFirstAuth(agent, true, AuthProbe{ParentAgentID: "template"})
+	if agent.SpreadGeneration != 0 || agent.ParentAgentID != LaunchTemplateParentAgentID {
+		t.Fatalf("%+v", agent)
+	}
+}