Add multi-staking entities, APY calculation, Asset Hub indexer support

- Add StakingApy, ActiveStaker, Reward entities to schema.graphql
- Add APY calculation engine in NewEra.ts (inflation curve + validator commission)
- Add saveMultiStakingReward to Rewards.ts and PoolRewards.ts
- Add handleAssetTransfer for assets.Transferred events
- Add constants.ts with genesis hashes and inflation params
- Add docker-compose.prod.yml for production deployment (relay + assethub nodes)
- Add deploy-vps.yml GitHub Actions workflow for auto-deploy on push

.github/workflows/deploy-vps.yml

@@ -0,0 +1,19 @@
+name: Deploy to VPS
+on:
+  push:
+    branches: [main]
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Deploy via SSH
+        uses: appleboy/ssh-action@v1
+        with:
+          host: ${{ secrets.VPS_HOST }}
+          username: root
+          key: ${{ secrets.VPS_SSH_KEY }}
+          script: |
+            cd /opt/subquery
+            git pull origin main
+            docker compose -f docker-compose.prod.yml pull
+            docker compose -f docker-compose.prod.yml up -d