security: remove all hardcoded API keys, require from environment

scripts/gpu/gpu_miner_host.py

@@ -14,8 +14,8 @@ from datetime import datetime
 
 # Configuration
 COORDINATOR_URL = "http://127.0.0.1:18000"
-MINER_ID = "REDACTED_MINER_KEY"
-AUTH_TOKEN = "REDACTED_MINER_KEY"
+MINER_ID = "${MINER_API_KEY}"
+AUTH_TOKEN = "${MINER_API_KEY}"
 HEARTBEAT_INTERVAL = 15
 MAX_RETRIES = 10
 RETRY_DELAY = 30