trellis and invokeAI urls configurable in config

Assets/_PROJECT/Scripts/ModeGeneration/ConfigManager.cs

@@ -0,0 +1,39 @@
+
+using System.IO;
+using UnityEngine;
+
+public class ConfigManager : MonoBehaviour
+{
+    public GameConfig Config { get; private set; }
+    public static ConfigManager Instance { get; private set; }
+    private static string configPath => Path.Combine(Application.persistentDataPath, "config.json");
+
+    private void Awake()
+    {
+        Instance = this;
+        LoadConfig();
+    }
+
+    public void LoadConfig()
+    {
+        if (File.Exists(configPath))
+        {
+            string json = File.ReadAllText(configPath);
+            Config = JsonUtility.FromJson<GameConfig>(json);
+        }
+        else
+        {
+            // Create config with default values
+            Config = new GameConfig();
+            SaveConfig();
+        }
+
+        Debug.Log("Loaded config from: " + configPath);
+    }
+
+    public void SaveConfig()
+    {
+        string json = JsonUtility.ToJson(Config, true);
+        File.WriteAllText(configPath, json);
+    }
+}