deploy: gen-suffixed container names + cameleer.generation label

Append an 8-char generation id (first 8 chars of deployment UUID) to:
- container name: {tenant}-{env}-{app}-{replica}-{gen}
- CAMELEER_AGENT_INSTANCEID (so old+new agents are distinct in the registry)
- Traefik cameleer.instance-id label

And emit a new standalone cameleer.generation label so dashboards
(Prometheus/Grafana) can pin deploy boundaries without regex on
instance-id.

Strategy branching comes next — this commit is foundation only; the
interim destroy-then-start flow still runs regardless of strategy.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cameleer-server-app/src/main/java/com/cameleer/server/app/runtime/DeploymentExecutor.java

@@ -89,6 +89,13 @@ public class DeploymentExecutor {
         this.applicationConfigRepository = applicationConfigRepository;
     }
 
+    /** Deployment-scoped id suffix — distinguishes container names and
+     * CAMELEER_AGENT_INSTANCEID across redeploys so old + new replicas can
+     * coexist during a blue/green swap. First 8 chars of the deployment UUID. */
+    static String generationOf(Deployment deployment) {
+        return deployment.id().toString().substring(0, 8);
+    }
+
     @Async("deploymentTaskExecutor")
     public void executeAsync(Deployment deployment) {
         long deployStart = System.currentTimeMillis();
@@ -96,6 +103,7 @@ public class DeploymentExecutor {
             App app = appService.getById(deployment.appId());
             Environment env = envService.getById(deployment.environmentId());
             String jarPath = appService.resolveJarPath(deployment.appVersionId());
+            String generation = generationOf(deployment);
 
             var globalDefaults = new ConfigMerger.GlobalRuntimeDefaults(
                     parseMemoryLimitMb(globalMemoryLimit),
@@ -192,11 +200,11 @@ public class DeploymentExecutor {
             List<String> newContainerIds = new ArrayList<>();
 
             for (int i = 0; i < config.replicas(); i++) {
-                String instanceId = env.slug() + "-" + app.slug() + "-" + i;
+                String instanceId = env.slug() + "-" + app.slug() + "-" + i + "-" + generation;
                 String containerName = tenantId + "-" + instanceId;
 
-                // Per-replica labels (include replica index and instance-id)
-                Map<String, String> labels = TraefikLabelBuilder.build(app.slug(), env.slug(), tenantId, config, i);
+                // Per-replica labels (include replica index, generation, and instance-id)
+                Map<String, String> labels = TraefikLabelBuilder.build(app.slug(), env.slug(), tenantId, config, i, generation);
                 labels.putAll(prometheusLabels);
 
                 // Per-replica env vars (set agent instance ID to match container log identity)

cameleer-server-app/src/main/java/com/cameleer/server/app/runtime/TraefikLabelBuilder.java

@@ -10,9 +10,13 @@ public final class TraefikLabelBuilder {
     private TraefikLabelBuilder() {}
 
     public static Map<String, String> build(String appSlug, String envSlug, String tenantId,
-                                              ResolvedContainerConfig config, int replicaIndex) {
+                                              ResolvedContainerConfig config, int replicaIndex,
+                                              String generation) {
+        // Traefik router/service keys stay generation-agnostic so load balancing
+        // spans old + new replicas during a blue/green overlap. instance-id and
+        // the new generation label carry the per-deploy identity.
         String svc = envSlug + "-" + appSlug;
-        String instanceId = envSlug + "-" + appSlug + "-" + replicaIndex;
+        String instanceId = envSlug + "-" + appSlug + "-" + replicaIndex + "-" + generation;
         Map<String, String> labels = new LinkedHashMap<>();
 
         labels.put("traefik.enable", "true");
@@ -21,6 +25,7 @@ public final class TraefikLabelBuilder {
         labels.put("cameleer.app", appSlug);
         labels.put("cameleer.environment", envSlug);
         labels.put("cameleer.replica", String.valueOf(replicaIndex));
+        labels.put("cameleer.generation", generation);
         labels.put("cameleer.instance-id", instanceId);
 
         labels.put("traefik.http.services." + svc + ".loadbalancer.server.port",