add --verbose flag and CASE_DEBUG env var, for debugging

main.py

@@ -104,6 +104,7 @@ def main() -> None:
     logging.getLogger().setLevel(logging.INFO)
 
     parser = argparse.ArgumentParser(description="toplevel cadquery interface")
+    parser.add_argument("--verbose", action="store_true", help="debug-level logging")
     parser.add_argument("--render-phone", action="store_true", help="render the case and also the phone within it; useful to confirm fit visually before printing")
     parser.add_argument("--render-phone-only", action="store_true", help="render *only* the phone, not even the case")
     parser.add_argument("--battery", choices=["none", "ldtek"], help="name of the battery for which to create a pocket cutout, or 'none'")
@@ -114,6 +115,10 @@ def main() -> None:
 
     args = parser.parse_args()
 
+    if args.verbose or os.environ.get("CASE_DEBUG"):
+        logging.getLogger().setLevel(logging.DEBUG)
+        logger.debug("enabled debug-level logging")
+
     config = Config.from_env()
 
     if args.render_phone: