```

chore: refactor logging module, update genesis timestamp, remove model relationships, and reorganize routers

- Rename logging.py to logger.py and update import paths in poa.py and main.py
- Update devnet genesis timestamp to 1766828620
- Remove SQLModel Relationship declarations from Block, Transaction, and Receipt models
- Add SessionDep type alias and get_session dependency in coordinator-api deps
- Reorganize coordinator-api routers: replace explorer/registry with exchange, users, marketplace

apps/blockchain-node/create_genesis.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+"""
+Simple script to create genesis block
+"""
+
+import sys
+sys.path.insert(0, 'src')
+
+from aitbc_chain.database import session_scope, init_db
+from aitbc_chain.models import Block
+from datetime import datetime
+import hashlib
+
+def compute_block_hash(height: int, parent_hash: str, timestamp: datetime) -> str:
+    """Compute block hash"""
+    data = f"{height}{parent_hash}{timestamp}".encode()
+    return hashlib.sha256(data).hexdigest()
+
+def create_genesis():
+    """Create the genesis block"""
+    print("Creating genesis block...")
+    
+    # Initialize database
+    init_db()
+    
+    # Check if genesis already exists
+    with session_scope() as session:
+        existing = session.exec(select(Block).order_by(Block.height.desc()).limit(1)).first()
+        if existing:
+            print(f"Genesis block already exists: #{existing.height}")
+            return
+        
+        # Create genesis block
+        timestamp = datetime.utcnow()
+        genesis_hash = compute_block_hash(0, "0x00", timestamp)
+        genesis = Block(
+            height=0,
+            hash=genesis_hash,
+            parent_hash="0x00",
+            proposer="ait-devnet-proposer",
+            timestamp=timestamp,
+            tx_count=0,
+            state_root=None,
+        )
+        session.add(genesis)
+        session.commit()
+        print(f"Genesis block created: #{genesis.height}")
+        print(f"Hash: {genesis.hash}")
+        print(f"Proposer: {genesis.proposer}")
+        print(f"Timestamp: {genesis.timestamp}")
+
+if __name__ == "__main__":
+    from sqlmodel import select
+    create_genesis()