Mod: mining rig, graphics cards, trading terminal, nightly settlement

First playable slice, tested in game on the test save:
- Network upgrade "Mining Access" (300) delivers a trading terminal, a
  mining rig and an RZX 50.
- The rig is a machine with a battery slot and four card slots; each night
  it draws its total power from the battery and its cards mine PSCoin.
  Cards show hashrate, power draw and condition, wear every night and can
  burn out. All state lives on item tags or in the mod save data.
- Trading terminal with wallet, trade (four pairs, deposit credits as CRC,
  withdraw CRC through the compliance desk) and report pages.
- Nightly log lines; exchange opening and halving news on the paper.
- English and Chinese text; sprites generated by art/sprites.py.

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

src/Decentralized/ModEntry.cs

@@ -0,0 +1,32 @@
+namespace Decentralized
+{
+    /// <summary>
+    /// mod 入口（游戏自带 mod 系统）。Init / OnEnable 在主菜单阶段调用：这里只订阅钩子、登记物品和人脉升级，
+    /// 不碰存档和店里的东西（那些在读档 / 新游戏的钩子里做）。
+    /// </summary>
+    public class ModEntry : IMod
+    {
+        public void Init(ModManifest manifest) { }
+
+        public void OnEnable()
+        {
+            Items.Subscribe();
+            Items.OpenTerminal = TerminalWindow.Open;
+            Unlock.Register();
+            Night.Subscribe();
+            ModHook.OnGameLoadedLate += Session.Load;
+            ModHook.OnNewGameStarted += OnNewGame;
+            Log.Info($"{ModInfo.Name} {ModInfo.Version} 已启用");
+        }
+
+        public void OnDisable()
+        {
+            Items.Unsubscribe();
+            Night.Unsubscribe();
+            ModHook.OnGameLoadedLate -= Session.Load;
+            ModHook.OnNewGameStarted -= OnNewGame;
+        }
+
+        private static void OnNewGame(string scenarioId) => Session.Load();
+    }
+}