Add smart ACK provider for WeChat MP replies

Replace fixed ackText with a rule-based AckProvider that picks
response templates by message type and intent (translate, summary,
rewrite, poster, ppt, mindmap, code, search, schedule). Pure sync,
zero I/O, auto-falls back to config.ackText on any error.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

schedule-reminder-worker.mjs

@@ -26,6 +26,17 @@ export function startScheduleReminderWorker({
             userId: subscription.userId,
             timezone: subscription.timezone,
           });
+          await scheduleService.createUserNotification?.({
+            userId: subscription.userId,
+            channel: 'web',
+            notificationType: 'todo_digest',
+            title: '今日待办摘要',
+            body: text,
+            data: {
+              subscriptionId: subscription.id,
+              timezone: subscription.timezone,
+            },
+          });
           await sendWechatTextToUser(subscription.userId, text);
           await scheduleService.logDelivery({
             subscriptionId: subscription.id,
@@ -46,6 +57,56 @@ export function startScheduleReminderWorker({
           await scheduleService.markDigestFailed(subscription, err, { maxAttempts });
         }
       }
+      const dueBalance = await scheduleService.listDueBalanceAlerts({ limit: 50 });
+      for (const candidate of dueBalance) {
+        const subscription = await scheduleService.lockBalanceAlert(candidate.id);
+        if (!subscription) continue;
+        try {
+          const user = await scheduleService.getUserWalletSnapshot?.(subscription.userId);
+          const balanceCents = Number(user?.balanceCents ?? user?.balance_cents ?? 0);
+          if (balanceCents > subscription.thresholdCents) {
+            await scheduleService.markBalanceAlertSent({
+              ...subscription,
+              lastNotifiedBalanceCents: balanceCents,
+            });
+            continue;
+          }
+          const yuan = (subscription.thresholdCents / 100).toFixed(2);
+          const text = `余额不足提醒\n\n你的账户余额已低于 ${yuan} 元，请及时充值。`;
+          await scheduleService.createUserNotification?.({
+            userId: subscription.userId,
+            channel: 'web',
+            notificationType: 'balance_low',
+            title: '余额不足提醒',
+            body: text,
+            data: {
+              thresholdCents: subscription.thresholdCents,
+              balanceCents,
+            },
+          });
+          await sendWechatTextToUser(subscription.userId, text);
+          await scheduleService.logDelivery({
+            subscriptionId: subscription.id,
+            userId: subscription.userId,
+            channel: subscription.channel,
+            status: 'success',
+          });
+          await scheduleService.markBalanceAlertSent({
+            ...subscription,
+            lastNotifiedBalanceCents: balanceCents,
+          });
+        } catch (err) {
+          logger.warn?.('Balance alert delivery failed:', err);
+          await scheduleService.logDelivery({
+            subscriptionId: subscription.id,
+            userId: subscription.userId,
+            channel: subscription.channel,
+            status: 'failed',
+            errorMessage: err instanceof Error ? err.message : String(err),
+          }).catch(() => {});
+          await scheduleService.markBalanceAlertFailed(subscription, err, { maxAttempts });
+        }
+      }
     } catch (err) {
       logger.warn?.('Schedule reminder worker failed:', err);
     } finally {