fix(mining-service): listen to correct CDC topic for contribution sync

Changed event handler to:
- Listen to 'cdc.contribution.outbox' topic (CDC/Debezium format)
- Handle 'ContributionAccountUpdated' events instead of 'ContributionCalculated'
- Use effectiveContribution for mining power calculation

This fixes the issue where mining accounts had zero totalContribution
because they weren't receiving contribution sync events.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/services/mining-service/src/application/event-handlers/contribution-event.handler.ts

@@ -1,43 +1,80 @@
-import { Injectable, Logger } from '@nestjs/common';
-import { EventPattern, Payload } from '@nestjs/microservices';
+import { Injectable, Logger, OnModuleInit } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
 import { ContributionSyncService } from '../services/contribution-sync.service';
+import { Kafka, Consumer, EachMessagePayload } from 'kafkajs';
 
 @Injectable()
-export class ContributionEventHandler {
+export class ContributionEventHandler implements OnModuleInit {
   private readonly logger = new Logger(ContributionEventHandler.name);
+  private consumer: Consumer;
 
-  constructor(private readonly syncService: ContributionSyncService) {}
+  constructor(
+    private readonly syncService: ContributionSyncService,
+    private readonly configService: ConfigService,
+  ) {}
 
-  @EventPattern('contribution.ContributionCalculated')
-  async handleContributionCalculated(@Payload() message: any): Promise<void> {
-    try {
-      const { payload } = message.value || message;
-      this.logger.debug(`Received ContributionCalculated event for ${payload.accountSequence}`);
+  async onModuleInit() {
+    const kafkaBrokers = this.configService.get<string>('KAFKA_BROKERS', 'localhost:9092');
+    const topic = this.configService.get<string>('CDC_TOPIC_CONTRIBUTION_OUTBOX', 'cdc.contribution.outbox');
 
-      await this.syncService.handleContributionCalculated({
-        accountSequence: payload.accountSequence,
-        personalContribution: payload.personalContribution,
-        calculatedAt: payload.calculatedAt,
+    const kafka = new Kafka({
+      clientId: 'mining-service',
+      brokers: kafkaBrokers.split(','),
     });
+
+    this.consumer = kafka.consumer({ groupId: 'mining-service-contribution-sync' });
+
+    try {
+      await this.consumer.connect();
+      await this.consumer.subscribe({ topic, fromBeginning: false });
+
+      await this.consumer.run({
+        eachMessage: async (payload: EachMessagePayload) => {
+          await this.handleMessage(payload);
+        },
+      });
+
+      this.logger.log(`Subscribed to ${topic} for contribution sync`);
     } catch (error) {
-      this.logger.error('Failed to handle ContributionCalculated event', error);
+      this.logger.error('Failed to connect to Kafka for contribution sync', error);
     }
   }
 
-  @EventPattern('contribution.DailySnapshotCreated')
-  async handleDailySnapshotCreated(@Payload() message: any): Promise<void> {
+  private async handleMessage(payload: EachMessagePayload): Promise<void> {
     try {
-      const { payload } = message.value || message;
-      this.logger.log(`Received DailySnapshotCreated event for ${payload.snapshotDate}`);
+      const { message } = payload;
+      if (!message.value) return;
+
+      const event = JSON.parse(message.value.toString());
+
+      // CDC 消息格式：{ after: { event_type, payload, ... } }
+      const data = event.after || event;
+      const eventType = data.event_type || data.eventType;
+      const eventPayload = typeof data.payload === 'string' ? JSON.parse(data.payload) : data.payload;
+
+      if (!eventPayload) return;
+
+      if (eventType === 'ContributionAccountUpdated') {
+        this.logger.debug(`Received ContributionAccountUpdated for ${eventPayload.accountSequence}`);
+
+        // 使用 effectiveContribution 作为挖矿算力
+        await this.syncService.handleContributionCalculated({
+          accountSequence: eventPayload.accountSequence,
+          personalContribution: eventPayload.effectiveContribution || eventPayload.totalContribution || '0',
+          calculatedAt: eventPayload.createdAt || new Date().toISOString(),
+        });
+      } else if (eventType === 'DailySnapshotCreated') {
+        this.logger.log(`Received DailySnapshotCreated for ${eventPayload.snapshotDate}`);
 
         await this.syncService.handleDailySnapshotCreated({
-        snapshotId: payload.snapshotId,
-        snapshotDate: payload.snapshotDate,
-        totalContribution: payload.totalContribution,
-        activeAccounts: payload.activeAccounts,
+          snapshotId: eventPayload.snapshotId,
+          snapshotDate: eventPayload.snapshotDate,
+          totalContribution: eventPayload.totalContribution,
+          activeAccounts: eventPayload.activeAccounts,
         });
+      }
     } catch (error) {
-      this.logger.error('Failed to handle DailySnapshotCreated event', error);
+      this.logger.error('Failed to handle contribution event', error);
     }
   }
 }