feat(framework): 收包路由分界(ActiveGame + Router)

C 规范 §4.1 的红线落地:
- platform/agent/room 三个 route → 平台 handlers(未注册显式抛错)
- 其他 route → activeGame.onReceive(rpc, data)(未激活或不匹配显式抛错)

ActiveGame: 当前子游戏槽(set/clear/get),进房时 setGame、离房 clear。
Router: 纯分发,不持状态。错误一律抛(第二准则:不静默吞包)。

128/128 tests pass, typecheck exit 0。

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

cocoscreator_projects/framework-tests/protocol/active-game.test.ts

@@ -0,0 +1,40 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { ActiveGame } from '../../YouleNexus/assets/framework/protocol/active-game.ts';
+import type { IGameModule, GameContext } from '../../YouleNexus/assets/framework/sdk/index.ts';
+
+class MockGame implements IGameModule {
+  readonly route = 'mock';
+  events: string[] = [];
+  onEnter(_ctx: GameContext): void { this.events.push('onEnter'); }
+  onExit(): void { this.events.push('onExit'); }
+  onReceive(rpc: string, _d: unknown): void { this.events.push(`onReceive:${rpc}`); }
+  onReconnect(_d: unknown): void { this.events.push('onReconnect'); }
+}
+
+test('初始: getGame 返回 null', () => {
+  assert.equal(new ActiveGame().get(), null);
+});
+
+test('setGame: 设置后 get 返回同一实例', () => {
+  const slot = new ActiveGame();
+  const g = new MockGame();
+  slot.set(g);
+  assert.equal(slot.get(), g);
+});
+
+test('clear: 清空后 get 返回 null', () => {
+  const slot = new ActiveGame();
+  slot.set(new MockGame());
+  slot.clear();
+  assert.equal(slot.get(), null);
+});
+
+test('set 覆盖前一个 game', () => {
+  const slot = new ActiveGame();
+  const g1 = new MockGame();
+  const g2 = new MockGame();
+  slot.set(g1);
+  slot.set(g2);
+  assert.equal(slot.get(), g2);
+});