feat: add smart_mode_free toggle — all users get smart mode when enabled

Server: subscription API returns active when smart_mode_free is true.
Admin console: add toggle switch in settings page under feature flags.
Default: true (free for all users during promotion period).

admin-console/src/views/SettingsView.vue

@@ -105,6 +105,15 @@
               <view class="toggle-dot"></view>
             </view>
           </view>
+          <view class="toggle-item">
+            <view class="toggle-info">
+              <text class="toggle-label">智能模式免费</text>
+              <text class="toggle-desc">开启后所有用户可免费使用智能模式</text>
+            </view>
+            <view class="toggle-switch" :class="{ on: settings.smart_mode_free }" @click="settings.smart_mode_free = !settings.smart_mode_free">
+              <view class="toggle-dot"></view>
+            </view>
+          </view>
           <view class="toggle-item">
             <view class="toggle-info">
               <text class="toggle-label">维护模式</text>
@@ -142,6 +151,7 @@ export default {
         enable_register: true,
         enable_binding: true,
         enable_free_mode: true,
+        smart_mode_free: true,
         maintenance_mode: false
       },
       timezoneOptions: ['Asia/Shanghai', 'Asia/Tokyo', 'America/New_York', 'Europe/London'],

server/src/routes/subscription.js

@@ -28,6 +28,10 @@ router.get('/subscription/plans', wrap(async (req, res) => {
 }))
 
 router.get('/subscription', requireUser, wrap(async (req, res) => {
+  const settings = await getSettings()
+  if (settings.smart_mode_free === true || settings.smart_mode_free === 'true') {
+    return res.json(ok({ status: 'active', plan: 'free', remaining_days: 9999, trial_used: false }))
+  }
   const sub = await subscriptionDao.findActive(req.user.user_id)
   const trialUsed = await subscriptionDao.findTrial(req.user.user_id)
   if (!sub) return res.json(ok({ status: 'inactive', plan: 'none', remaining_days: 0, trial_used: !!trialUsed }))