```

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/init_genesis.py

@@ -0,0 +1,53 @@
+#!/usr/bin/env python3
+"""
+Initialize genesis block for AITBC blockchain
+"""
+
+import sys
+sys.path.insert(0, 'src')
+
+from dataclasses import dataclass
+from aitbc_chain.database import session_scope
+from aitbc_chain.models import Block
+from aitbc_chain.consensus.poa import PoAProposer, ProposerConfig
+from datetime import datetime
+
+def init_genesis():
+    """Initialize the genesis block"""
+    print("Initializing genesis block...")
+    
+    # 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 proposer config
+    config = ProposerConfig(
+        chain_id="ait-devnet",
+        proposer_id="ait-devnet-proposer",
+        interval_seconds=2,
+    )
+    
+    # Create proposer and initialize genesis
+    proposer = PoAProposer(config=config, session_factory=session_scope)
+    
+    # The _ensure_genesis_block method is called during proposer initialization
+    # but we need to trigger it manually
+    proposer._ensure_genesis_block()
+    
+    print("Genesis block created successfully!")
+    
+    # Verify
+    with session_scope() as session:
+        genesis = session.exec(select(Block).where(Block.height == 0)).first()
+        if genesis:
+            print(f"Genesis block: #{genesis.height}")
+            print(f"Hash: {genesis.hash}")
+            print(f"Proposer: {genesis.proposer}")
+            print(f"Timestamp: {genesis.timestamp}")
+
+if __name__ == "__main__":
+    from sqlmodel import select
+    init_genesis()