chore: initialize monorepo with project scaffolding, configs, and CI setup

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

@@ -0,0 +1,30 @@
+from __future__ import annotations
+
+from pathlib import Path
+from typing import Optional
+
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+
+class ChainSettings(BaseSettings):
+    model_config = SettingsConfigDict(env_file=".env", env_file_encoding="utf-8", case_sensitive=False)
+
+    chain_id: str = "ait-devnet"
+    db_path: Path = Path("./data/chain.db")
+
+    rpc_bind_host: str = "127.0.0.1"
+    rpc_bind_port: int = 8080
+
+    p2p_bind_host: str = "0.0.0.0"
+    p2p_bind_port: int = 7070
+
+    proposer_id: str = "ait-devnet-proposer"
+    proposer_key: Optional[str] = None
+
+    mint_per_unit: int = 1000
+    coordinator_ratio: float = 0.05
+
+    block_time_seconds: int = 2
+
+
+settings = ChainSettings()