refactor: move JOB_FETCH_BITCOIN_PRICE constant to worker.py

Unlike JOB_RANDOM_NUMBER which is used for external job enqueueing,
JOB_FETCH_BITCOIN_PRICE is only used internally by the scheduler.
Move it to worker.py to clarify it's not part of the public job API.

backend/jobs.py

@@ -10,7 +10,6 @@ from database import ASYNCPG_DATABASE_URL
 
 # Job type constants
 JOB_RANDOM_NUMBER = "random_number"
-JOB_FETCH_BITCOIN_PRICE = "fetch_bitcoin_price"
 
 # Connection pool for job enqueueing (lazy initialized)
 _pool: asyncpg.Pool | None = None

backend/worker.py

@@ -13,9 +13,12 @@ from pgqueuer.models import Schedule
 from pgqueuer.queries import Queries
 
 from database import ASYNCPG_DATABASE_URL
-from jobs import JOB_FETCH_BITCOIN_PRICE, JOB_RANDOM_NUMBER
+from jobs import JOB_RANDOM_NUMBER
 from price_fetcher import PAIR_BTC_EUR, SOURCE_BITFINEX, fetch_btc_eur_price
 
+# Scheduled job type (internal to worker, not enqueued externally)
+JOB_FETCH_BITCOIN_PRICE = "fetch_bitcoin_price"
+
 logging.basicConfig(
     level=logging.INFO,
     format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",