fix: resolve syntax errors in scan-skipped files

- Fix malformed f-strings in agent communication SDK
- Repair pricing strategy delimiters and optimizer blocks
- Normalize FastAPI session dependency signatures in routers
- Fix incomplete constructor, indentation, and empty exception blocks
- Restore syntax validity for files previously skipped by Bandit

apps/exchange/bitcoin-wallet.py

@@ -6,7 +6,7 @@ Bitcoin Wallet Integration for AITBC Trade Exchange
 import os
 import json
 import hashlib
- import hmac
+import hmac
 import time
 from typing import Dict, Optional, Tuple
 from dataclasses import dataclass