修复拼图生成前订阅授权

新增小程序原生订阅消息授权页，在用户点击后请求生成结果通知授权。

拼图 compile_puzzle_draft 前等待授权页返回或跳过后再发起生成 action。

移除 web-view message 订阅授权路径，改用 storage/hash 回写订阅结果。

补充订阅授权测试、文档和团队踩坑记录。

src/services/wechatMiniProgramSubscribe.test.ts

@@ -0,0 +1,58 @@
+/* @vitest-environment jsdom */
+
+import { afterEach, describe, expect, test, vi } from 'vitest';
+
+import {
+  requestGenerationResultSubscribePermission,
+} from './wechatMiniProgramSubscribe';
+
+describe('wechatMiniProgramSubscribe', () => {
+  afterEach(() => {
+    window.history.replaceState(null, '', '/');
+    window.wx = undefined;
+  });
+
+  test('requests generation result subscription permission through native mini program page', async () => {
+    const navigateTo = vi.fn((options) => {
+      options.success?.();
+      window.setTimeout(() => {
+        window.location.hash = 'wx_subscribe_result=req-1:success';
+        window.dispatchEvent(new HashChangeEvent('hashchange'));
+      }, 0);
+    });
+    window.history.replaceState(
+      null,
+      '',
+      '/creation/puzzle?clientRuntime=wechat_mini_program',
+    );
+    window.wx = {
+      miniProgram: {
+        navigateTo,
+      },
+    };
+
+    const requested = await requestGenerationResultSubscribePermission();
+
+    expect(requested).toBe(true);
+    expect(navigateTo).toHaveBeenCalledWith({
+      url: expect.stringMatching(/^\/pages\/subscribe-message\/index\?/u),
+      success: expect.any(Function),
+      fail: expect.any(Function),
+    });
+    expect(window.location.hash).toBe('');
+  });
+
+  test('skips permission request outside mini program web-view', async () => {
+    const navigateTo = vi.fn();
+    window.wx = {
+      miniProgram: {
+        navigateTo,
+      },
+    };
+
+    const requested = await requestGenerationResultSubscribePermission();
+
+    expect(requested).toBe(false);
+    expect(navigateTo).not.toHaveBeenCalled();
+  });
+});