add LoadFolders patch to dynamically load mod directories based on platform branch

Patches/Features/LoadFoldersPatch.cs

@@ -0,0 +1,52 @@
+using System.Text.Json;
+using HarmonyLib;
+using MegaCrit.Sts2.Core.Modding;
+using MegaCrit.Sts2.Core.Platform;
+
+namespace BaseLib.Patches.Features;
+
+[HarmonyPatch(typeof(ModManager), "TryLoadMod")]
+public static class LoadFoldersPatch
+{
+    [HarmonyPrefix]
+    private static void Prefix(Mod mod)
+    {
+        var loadFoldersPath = Path.Combine(mod.path, "loadFolders");
+        if (!File.Exists(loadFoldersPath))
+            return;
+
+        try
+        {
+            var json = File.ReadAllText(loadFoldersPath);
+            var map = JsonSerializer.Deserialize<Dictionary<string, string>>(json);
+
+            if (map == null)
+            {
+                BaseLibMain.Logger.Warn($"[LoadFolders] {mod.manifest?.id}: loadFolders deserialized to null");
+                return;
+            }
+
+            var branch = PlatformUtil.GetPlatformBranch();
+            var branchName = branch.ToName();
+
+            if (!map.TryGetValue(branchName, out var subdir))
+            {
+                BaseLibMain.Logger
+                    .Info($"[LoadFolders] {mod.manifest?.id}: no entry for branch '{branchName}', loading from root");
+                return;
+            }
+
+            subdir = subdir.TrimStart('/', '\\');
+            var resolvedPath = Path.Combine(mod.path, subdir);
+
+            BaseLibMain.Logger
+                .Info($"[LoadFolders] {mod.manifest?.id}: loading folder '{resolvedPath}' for branch '{branchName}'");
+
+            mod.path = resolvedPath;
+        }
+        catch (Exception e)
+        {
+            BaseLibMain.Logger.Warn($"[LoadFolders] {mod.manifest?.id}: failed to process loadFolders: {e}");
+        }
+    }
+}