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/message-router.js

@@ -386,64 +386,6 @@
             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 (typeof markCurrentRegistrationAccountUsed === 'function') {
-            await markCurrentRegistrationAccountUsed(latestState, {
-              logPrefix: '流程完成',
-              level: 'ok',
-            });
-          } else 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 (typeof markCurrentRegistrationAccountUsed !== 'function' && String(latestState.mailProvider || '').trim().toLowerCase() === '2925' && latestState.currentMail2925AccountId) {
-            await patchMail2925Account(latestState.currentMail2925AccountId, {
-              lastUsedAt: Date.now(),
-              lastError: '',
-            });
-            await addLog('当前 2925 账号已记录最近使用时间。', 'ok');
-          }
-          if (typeof markCurrentRegistrationAccountUsed !== 'function' && 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,
-            });
-          }
-          if (typeof markCurrentRegistrationAccountUsed !== 'function') {
-            await finalizeIcloudAliasAfterSuccessfulFlow(latestState);
-          }
-          if (typeof markCurrentRegistrationAccountUsed !== 'function' && typeof markCurrentCustomEmailPoolEntryUsed === 'function') {
-            await markCurrentCustomEmailPoolEntryUsed(latestState);
-          }
-          if (typeof finalizePhoneActivationAfterSuccessfulFlow === 'function') {
-            await finalizePhoneActivationAfterSuccessfulFlow(latestState);
-          }
-          break;
-        }
         default:
           break;
       }