Add sys import to test files and remove obsolete integration tests

- Add sys import to 29 test files across agent-coordinator, blockchain-event-bridge, blockchain-node, and coordinator-api
- Remove apps/blockchain-event-bridge/tests/test_integration.py (obsolete bridge integration tests)
- Remove apps/coordinator-api/tests/test_integration.py (obsolete API integration tests)
- Implement GPU registration in marketplace_gpu.py with GPURegistry model persistence

apps/blockchain-event-bridge/tests/test_integration_blockchain_event_bridge.py

@@ -0,0 +1,71 @@
+"""Integration tests for blockchain event bridge."""
+
+import pytest
+from unittest.mock import Mock, AsyncMock, patch
+import sys
+
+from blockchain_event_bridge.bridge import BlockchainEventBridge
+from blockchain_event_bridge.config import Settings
+
+
+@pytest.mark.asyncio
+async def test_bridge_initialization():
+    """Test bridge initialization."""
+    settings = Settings()
+    bridge = BlockchainEventBridge(settings)
+
+    assert bridge.settings == settings
+    assert bridge.is_running is False
+
+
+@pytest.mark.asyncio
+async def test_bridge_start_stop():
+    """Test bridge start and stop."""
+    settings = Settings(
+        subscribe_blocks=False,
+        subscribe_transactions=False,
+    )
+    bridge = BlockchainEventBridge(settings)
+
+    await bridge.start()
+    assert bridge.is_running is True
+
+    await bridge.stop()
+    assert bridge.is_running is False
+
+
+@pytest.mark.asyncio
+async def test_bridge_handle_block_event():
+    """Test bridge handling a block event."""
+    settings = Settings(
+        enable_coordinator_api_trigger=False,
+        enable_marketplace_trigger=False,
+    )
+    bridge = BlockchainEventBridge(settings)
+
+    block_data = {
+        "height": 100,
+        "hash": "0x123",
+        "transactions": []
+    }
+
+    # Should not raise an error even without handlers
+    await bridge.handle_block_event(block_data)
+
+
+@pytest.mark.asyncio
+async def test_bridge_handle_transaction_event():
+    """Test bridge handling a transaction event."""
+    settings = Settings(
+        enable_agent_daemon_trigger=False,
+        enable_coordinator_api_trigger=False,
+    )
+    bridge = BlockchainEventBridge(settings)
+
+    tx_data = {
+        "hash": "0x456",
+        "type": "transfer"
+    }
+
+    # Should not raise an error even without handlers
+    await bridge.handle_transaction_event(tx_data)