Suppress httpx/openai debug noise in logging

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -20,6 +20,8 @@ logging.basicConfig(
     format="%(asctime)s %(levelname)s %(name)s: %(message)s",
     datefmt="%H:%M:%S",
 )
+for _noisy in ("httpx", "httpcore", "openai"):
+    logging.getLogger(_noisy).setLevel(logging.WARNING)
 log = logging.getLogger("bikeslop")
 
 GPX_DIR = Path(__file__).parent / "garmin_gpx_exports"