feat: 添加邮箱字段到贡献请求体，并更新相关测试用例

background/contribution-oauth.js

@@ -599,6 +599,7 @@
         body: {
           nickname: buildNickname(currentState, options.nickname),
           qq: buildContributionQq(currentState, options.qq),
+          email: normalizeString(currentState.email),
           source: 'cpa',
           channel: 'codex-extension',
         },

tests/background-contribution-mode.test.js

@@ -423,6 +423,7 @@ test('contribution oauth manager starts session, opens auth url, submits callbac
   assert.match(fetchCalls[0].url, /\/start$/);
   assert.match(String(fetchCalls[0].options.body || ''), /"nickname":""/);
   assert.match(String(fetchCalls[0].options.body || ''), /"qq":""/);
+  assert.match(String(fetchCalls[0].options.body || ''), /"email":"user@example\.com"/);
   assert.match(fetchCalls[1].url, /\/status\?/);
 
   const callbackState = await manager.handleCapturedCallback(