MSCO 2.10.0: mod support, ESC no longer quits from the main menu

- MscoMod API (ModApi.cs) and ModLoader: own mods from MSCO\Mods, hooks for menu/game/update/GUI,
  session and player events, Send/OnMessage between players (MsgType.ModMessage)
- Server mods: ModList before Welcome, consent prompt (INSTALL & JOIN), download with SHA-256 check
  into MSCO\Mods\Servers, active only on that server; game start waits for the download
- Mods page in the MSCO menu, console command "mods"
- Server browser: MODS pill, VANILLA/MODDED filters, mod list in the server profile
- PlayMaker ApplicationQuit is ignored in the main menu (ESC used to close the game)
- MODDING.md and examples/HelloMod

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

SafetyPatches.cs

@@ -42,6 +42,41 @@ namespace MSCO
             {
                 MscoLog.Warning("[MSCO] Could not install hierarchy guard: " + e.Message);
             }
+            PatchMenuQuit();
+        }
+
+        /// <summary>
+        /// ESC im Hauptmenü beendet beim Spiel sofort das Programm (PlayMaker-Aktion "ApplicationQuit" im Menü). Im
+        /// MSCO-Hauptmenü gibt es dafür den QUIT-Knopf - dort also nicht über die Spiel-Logik beenden. Im Spiel selbst
+        /// (Pausemenü) bleibt alles wie gehabt.
+        /// </summary>
+        static void PatchMenuQuit()
+        {
+            try
+            {
+                Type action = null;
+                foreach (Assembly asm in AppDomain.CurrentDomain.GetAssemblies())
+                {
+                    action = asm.GetType("HutongGames.PlayMaker.Actions.ApplicationQuit");
+                    if (action != null) break;
+                }
+                MethodInfo onEnter = action != null ? action.GetMethod("OnEnter", BindingFlags.Instance | BindingFlags.Public) : null;
+                if (onEnter == null) return;
+                HarmonyInstance.Create("mbm.msco.menuquit").Patch(onEnter,
+                    new HarmonyMethod(typeof(SafetyPatches).GetMethod("QuitPrefix", BindingFlags.Static | BindingFlags.NonPublic)), null);
+            }
+            catch (Exception e)
+            {
+                MscoLog.Warning("[MSCO] Could not block ESC-quit in the main menu: " + e.Message);
+            }
+        }
+
+        static bool QuitPrefix(FsmStateAction __instance)
+        {
+            if (!MenuHelper.InMenu) return true;
+            MscoLog.Info("[MSCO] The game tried to quit from the main menu (ESC) - use QUIT in the MSCO menu to exit");
+            try { __instance.Finish(); } catch { }
+            return false;
         }
 
         static bool SetParentPrefix(FsmStateAction __instance)