feat(deploy): externalRouting toggle to keep apps off Traefik

Adds a boolean `externalRouting` flag (default `true`) on
ResolvedContainerConfig. When `false`, TraefikLabelBuilder emits only
the identity labels (`managed-by`, `cameleer.*`) and skips every
`traefik.*` label, so the container is not published by Traefik.
Sibling containers on `cameleer-traefik` / `cameleer-env-{tenant}-{env}`
can still reach it via Docker DNS on whatever port the app listens on.

TDD: new TraefikLabelBuilderTest covers enabled (default labels present),
disabled (zero traefik.* labels), and disabled (identity labels retained)
cases. Full module unit suite: 208/0/0.

Plumbed through ConfigMerger read, DeploymentExecutor snapshot, UI form
state, Resources tab toggle, POST payload, and snapshot-to-form mapping.
Rule files updated.

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

@@ -605,6 +605,7 @@ public class DeploymentExecutor {
         map.put("runtimeType", config.runtimeType());
         map.put("customArgs", config.customArgs());
         map.put("extraNetworks", config.extraNetworks());
+        map.put("externalRouting", config.externalRouting());
         return map;
     }
 }

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

@@ -19,7 +19,6 @@ public final class TraefikLabelBuilder {
         String instanceId = envSlug + "-" + appSlug + "-" + replicaIndex + "-" + generation;
         Map<String, String> labels = new LinkedHashMap<>();
 
-        labels.put("traefik.enable", "true");
         labels.put("managed-by", "cameleer-server");
         labels.put("cameleer.tenant", tenantId);
         labels.put("cameleer.app", appSlug);
@@ -28,6 +27,11 @@ public final class TraefikLabelBuilder {
         labels.put("cameleer.generation", generation);
         labels.put("cameleer.instance-id", instanceId);
 
+        if (!config.externalRouting()) {
+            return labels;
+        }
+
+        labels.put("traefik.enable", "true");
         labels.put("traefik.http.services." + svc + ".loadbalancer.server.port",
                 String.valueOf(config.appPort()));