```

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/src/aitbc_chain/consensus/poa.py

@@ -9,7 +9,7 @@ from typing import Callable, ContextManager, Optional
 
 from sqlmodel import Session, select
 
-from ..logging import get_logger
+from ..logger import get_logger
 from ..metrics import metrics_registry
 
 

apps/blockchain-node/src/aitbc_chain/main.py

@@ -7,7 +7,7 @@ from typing import Optional
 from .config import settings
 from .consensus import PoAProposer, ProposerConfig
 from .database import init_db, session_scope
-from .logging import get_logger
+from .logger import get_logger
 
 logger = get_logger(__name__)
 

apps/blockchain-node/src/aitbc_chain/models.py

@@ -8,6 +8,7 @@ from pydantic import field_validator
 from sqlalchemy import Column
 from sqlalchemy.types import JSON
 from sqlmodel import Field, Relationship, SQLModel
+from sqlalchemy.orm import Mapped
 
 _HEX_PATTERN = re.compile(r"^(0x)?[0-9a-fA-F]+$")
 
@@ -34,9 +35,6 @@ class Block(SQLModel, table=True):
     tx_count: int = 0
     state_root: Optional[str] = None
 
-    transactions: list["Transaction"] = Relationship(back_populates="block")
-    receipts: list["Receipt"] = Relationship(back_populates="block")
-
     @field_validator("hash", mode="before")
     @classmethod
     def _hash_is_hex(cls, value: str) -> str:
@@ -69,8 +67,6 @@ class Transaction(SQLModel, table=True):
     )
     created_at: datetime = Field(default_factory=datetime.utcnow, index=True)
 
-    block: Optional["Block"] = Relationship(back_populates="transactions")
-
     @field_validator("tx_hash", mode="before")
     @classmethod
     def _tx_hash_is_hex(cls, value: str) -> str:
@@ -101,8 +97,6 @@ class Receipt(SQLModel, table=True):
     minted_amount: Optional[int] = None
     recorded_at: datetime = Field(default_factory=datetime.utcnow, index=True)
 
-    block: Optional["Block"] = Relationship(back_populates="receipts")
-
     @field_validator("receipt_id", mode="before")
     @classmethod
     def _receipt_id_is_hex(cls, value: str) -> str: