Add blockchain event bridge service with smart contract event integration

- Phase 1: Core bridge service with gossip broker subscription
- Phase 2: Smart contract event integration via eth_getLogs RPC endpoint
- Add contract event subscriber for AgentStaking, PerformanceVerifier, Marketplace, Bounty, CrossChainBridge
- Add contract event handlers in agent_daemon.py and marketplace.py
- Add systemd service file for blockchain-event-bridge
- Update blockchain node router.py with eth_getLogs endpoint
- Add configuration for contract addresses
- Add tests for contract subscriber and handlers (27 tests passing)

apps/blockchain-event-bridge/src/blockchain_event_bridge/polling/batch.py

@@ -0,0 +1,70 @@
+"""Batch processing for aggregated operations."""
+
+import asyncio
+import logging
+from typing import Any, Dict, List
+
+logger = logging.getLogger(__name__)
+
+
+class BatchProcessor:
+    """Processes events in batches for efficiency."""
+
+    def __init__(self, settings: Any) -> None:
+        self.settings = settings
+        self._running = False
+        self._batch_queue: List[Dict[str, Any]] = []
+        self._batch_size = 50
+
+    async def run(self) -> None:
+        """Run the batch processor."""
+        if not self.settings.enable_polling:
+            logger.info("Batch processing disabled")
+            return
+
+        self._running = True
+        logger.info("Starting batch processor...")
+
+        while self._running:
+            try:
+                await self._process_batch()
+                await asyncio.sleep(self.settings.polling_interval_seconds)
+            except asyncio.CancelledError:
+                logger.info("Batch processor cancelled")
+                break
+            except Exception as e:
+                logger.error(f"Error in batch processor: {e}", exc_info=True)
+                await asyncio.sleep(5)
+
+    async def add_to_batch(self, event: Dict[str, Any]) -> None:
+        """Add an event to the batch queue."""
+        self._batch_queue.append(event)
+
+        if len(self._batch_queue) >= self._batch_size:
+            await self._process_batch()
+
+    async def _process_batch(self) -> None:
+        """Process the current batch of events."""
+        if not self._batch_queue:
+            return
+
+        batch = self._batch_queue.copy()
+        self._batch_queue.clear()
+
+        logger.info(f"Processing batch of {len(batch)} events")
+
+        # Placeholder for Phase 3 implementation
+        # Examples:
+        # - Batch agent reputation updates
+        # - Batch marketplace state synchronization
+        # - Batch performance metric aggregation
+
+    async def stop(self) -> None:
+        """Stop the batch processor."""
+        self._running = False
+
+        # Process remaining events
+        if self._batch_queue:
+            await self._process_batch()
+
+        logger.info("Batch processor stopped")