refactor: route platform verification completion by step key

- 删除平台验证完成后的 step 10/13 数字兜底收尾逻辑，统一由 platform-verify stepKey 入口处理。

- 调整 LuckMail 与 localhost 清理测试，改为验证 message-router 的语义路由入口。

- 保留平台验证成功后的账号、邮箱、手机号接码收尾能力，但不再依赖硬编码步骤号。

background.js

@@ -7816,56 +7816,6 @@ async function handleStepData(step, payload) {
         broadcastDataUpdate({ localhostUrl: payload.localhostUrl });
       }
       break;
-    case 10:
-    case 13: {
-      if (payload.localhostUrl) {
-        await closeLocalhostCallbackTabs(payload.localhostUrl);
-      }
-      const latestState = await getState();
-      const lastStepId = typeof getLastStepIdForState === 'function'
-        ? getLastStepIdForState(latestState)
-        : 10;
-      if (Number(step) !== Number(lastStepId)) {
-        break;
-      }
-      if (latestState.currentHotmailAccountId && isHotmailProvider(latestState)) {
-        await patchHotmailAccount(latestState.currentHotmailAccountId, {
-          used: true,
-          lastUsedAt: Date.now(),
-        });
-        await addLog('当前 Hotmail 账号已自动标记为已用。', 'ok');
-      }
-      if (isLuckmailProvider(latestState)) {
-        const currentPurchase = getCurrentLuckmailPurchase(latestState);
-        if (currentPurchase?.id) {
-          await setLuckmailPurchaseUsedState(currentPurchase.id, true);
-          await addLog(`当前 LuckMail 邮箱 ${currentPurchase.email_address} 已在本地标记为已用。`, 'ok');
-        }
-        await clearLuckmailRuntimeState({ clearEmail: true });
-        await addLog('当前 LuckMail 邮箱运行态已清空，下轮将优先复用未用邮箱或重新购买邮箱。', 'ok');
-      }
-      const localhostPrefix = buildLocalhostCleanupPrefix(payload.localhostUrl);
-      if (localhostPrefix) {
-        await closeTabsByUrlPrefix(localhostPrefix, {
-          excludeUrls: [payload.localhostUrl],
-          excludeLocalhostCallbacks: true,
-        });
-      }
-      await finalizeIcloudAliasAfterSuccessfulFlow(latestState);
-      if (typeof markCurrentCustomEmailPoolEntryUsed === 'function') {
-        await markCurrentCustomEmailPoolEntryUsed(latestState);
-      }
-      const shouldClearCustomPoolEmail = String(latestState?.emailGenerator || '').trim().toLowerCase() === (
-        typeof CUSTOM_EMAIL_POOL_GENERATOR === 'string'
-          ? CUSTOM_EMAIL_POOL_GENERATOR
-          : 'custom-pool'
-      );
-      if ((shouldUseCustomRegistrationEmail(latestState) || shouldClearCustomPoolEmail) && latestState.email) {
-        await setEmailStateSilently(null);
-      }
-      await finalizePhoneActivationAfterSuccessfulFlow(latestState);
-      break;
-    }
   }
 }