feat: add extra Docker networks to container config

Apps can now join additional Docker networks (e.g., monitoring,
prometheus) configured via containerConfig.extraNetworks. Flows through
the 3-layer config merge. Networks are created if absent and containers
are connected during deployment. UI adds a pill-list field on the
Resources tab (both create and edit views).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-core/src/main/java/com/cameleer3/server/core/runtime/ConfigMerger.java

@@ -32,7 +32,8 @@ public final class ConfigMerger {
                 boolVal(appConfig, envConfig, "routeControlEnabled", true),
                 boolVal(appConfig, envConfig, "replayEnabled", true),
                 stringVal(appConfig, envConfig, "runtimeType", "auto"),
-                stringVal(appConfig, envConfig, "customArgs", "")
+                stringVal(appConfig, envConfig, "customArgs", ""),
+                stringList(appConfig, envConfig, "extraNetworks")
         );
     }
 
@@ -78,6 +79,17 @@ public final class ConfigMerger {
         return List.of();
     }
 
+    private static List<String> stringList(Map<String, Object> app, Map<String, Object> env, String key) {
+        Object val = app.containsKey(key) ? app.get(key) : env.get(key);
+        if (val instanceof List<?> list) {
+            return list.stream()
+                    .filter(String.class::isInstance)
+                    .map(String.class::cast)
+                    .toList();
+        }
+        return List.of();
+    }
+
     @SuppressWarnings("unchecked")
     private static Map<String, String> stringMap(Map<String, Object> app, Map<String, Object> env, String key) {
         Object val = app.containsKey(key) ? app.get(key) : env.get(key);

cameleer3-server-core/src/main/java/com/cameleer3/server/core/runtime/ResolvedContainerConfig.java

@@ -21,7 +21,8 @@ public record ResolvedContainerConfig(
         boolean routeControlEnabled,
         boolean replayEnabled,
         String runtimeType,
-        String customArgs
+        String customArgs,
+        List<String> extraNetworks
 ) {
     public long memoryLimitBytes() {
         return (long) memoryLimitMb * 1024 * 1024;