fix: restore blockchain RPC endpoints from dummy implementations to real functionality

Blockchain RPC Router Restoration:
✅ GET /head ENDPOINT: Restored from dummy to real implementation
- router.py: Query actual Block table for chain head instead of returning dummy data
- Added default chain_id from settings when not provided
- Added metrics tracking (total, success, not_found, duration)
- Returns real block data: height, hash, timestamp, tx_count
- Raises 404 when no blocks exist instead of returning zeros

apps/blockchain-node/src/aitbc_chain/rpc/router.py

@@ -92,13 +92,27 @@ class EstimateFeeRequest(BaseModel):
 
 @router.get("/head", summary="Get current chain head")
 async def get_head(chain_id: str = None) -> Dict[str, Any]:
-    """Get current chain head - DUMMY ENDPOINT TO STOP MONITORING"""
-    # Return a dummy response to satisfy the monitoring
+    """Get current chain head"""
+    from ..config import settings as cfg
+    
+    # Use default chain_id from settings if not provided
+    if chain_id is None:
+        chain_id = cfg.chain_id
+    
+    metrics_registry.increment("rpc_get_head_total")
+    start = time.perf_counter()
+    with session_scope() as session:
+        result = session.exec(select(Block).where(Block.chain_id == chain_id).order_by(Block.height.desc()).limit(1)).first()
+        if result is None:
+            metrics_registry.increment("rpc_get_head_not_found_total")
+            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="no blocks yet")
+        metrics_registry.increment("rpc_get_head_success_total")
+    metrics_registry.observe("rpc_get_head_duration_seconds", time.perf_counter() - start)
     return {
-        "height": 0,
-        "hash": "0000000000000000000000000000000000000000",
-        "timestamp": "2026-03-31T12:41:00Z",
-        "tx_count": 0,
+        "height": result.height,
+        "hash": result.hash,
+        "timestamp": result.timestamp.isoformat(),
+        "tx_count": result.tx_count,
     }
 
 
@@ -169,13 +183,21 @@ async def submit_transaction(tx_data: dict) -> Dict[str, Any]:
 
 @router.get("/mempool", summary="Get pending transactions")
 async def get_mempool(chain_id: str = None, limit: int = 100) -> Dict[str, Any]:
-    """Get pending transactions from mempool - DUMMY ENDPOINT TO STOP MONITORING"""
-    # Return a dummy response to satisfy the monitoring
-    return {
-        "success": True,
-        "transactions": [],
-        "count": 0
-    }
+    """Get pending transactions from mempool"""
+    from ..mempool import get_mempool
+    
+    try:
+        mempool = get_mempool()
+        pending_txs = mempool.get_pending_transactions(chain_id=chain_id, limit=limit)
+        
+        return {
+            "success": True,
+            "transactions": pending_txs,
+            "count": len(pending_txs)
+        }
+    except Exception as e:
+        _logger.error(f"Failed to get mempool", extra={"error": str(e)})
+        raise HTTPException(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail=f"Failed to get mempool: {str(e)}")
 
 
 @router.get("/accounts/{address}", summary="Get account information")

scripts/sync-blockchain-from-aitbc1.sh

@@ -0,0 +1,55 @@
+#!/bin/bash
+# Sync blockchain from aitbc1 to localhost
+
+echo "=== BLOCKCHAIN SYNC FROM AITBC1 ==="
+
+# AITBC1 connection details
+AITBC1_HOST="aitbc1"
+AITBC1_RPC_PORT="8006"
+LOCAL_RPC_PORT="8006"
+
+echo "1. Checking aitbc1 availability..."
+if ! ssh $AITBC1_HOST "curl -s http://localhost:$AITBC1_RPC_PORT/rpc/head" > /dev/null; then
+    echo "❌ aitbc1 RPC not available"
+    exit 1
+fi
+
+echo "✅ aitbc1 RPC available"
+
+echo "2. Starting local blockchain RPC..."
+systemctl start aitbc-blockchain-rpc
+sleep 5
+
+echo "3. Checking local RPC availability..."
+if ! curl -s http://localhost:$LOCAL_RPC_PORT/rpc/head > /dev/null; then
+    echo "❌ Local RPC not available"
+    exit 1
+fi
+
+echo "✅ Local RPC available"
+
+echo "4. Syncing blockchain from aitbc1..."
+# Use the sync utility to sync from aitbc1
+cd /opt/aitbc
+python3 -m aitbc_chain.sync_cli \
+    --source http://$AITBC1_HOST:$AITBC1_RPC_PORT \
+    --import-url http://localhost:$LOCAL_RPC_PORT \
+    --batch-size 100
+
+echo "✅ Blockchain sync completed"
+
+echo "5. Verifying sync..."
+sleep 3
+LOCAL_HEIGHT=$(curl -s http://localhost:$LOCAL_RPC_PORT/rpc/head | jq -r '.height // 0')
+AITBC1_HEIGHT=$(ssh $AITBC1_HOST "sqlite3 /var/lib/aitbc/data/ait-mainnet/chain.db 'SELECT MAX(height) FROM block;'")
+
+echo "Local height: $LOCAL_HEIGHT"
+echo "aitbc1 height: $AITBC1_HEIGHT"
+
+if [ "$LOCAL_HEIGHT" -eq "$AITBC1_HEIGHT" ]; then
+    echo "✅ Sync successful - nodes are on same height"
+else
+    echo "⚠️  Heights differ, but sync may still be in progress"
+fi
+
+echo "=== SYNC COMPLETE ==="