Expose smoke case listing

tools/prompt_smoke.py

@@ -8913,6 +8913,11 @@ SMOKE_CASES: list[tuple[str, Callable[[], None]]] = [
 
 def main(argv: list[str] | None = None) -> int:
     parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument(
+        "--list",
+        action="store_true",
+        help="List available smoke case names and exit.",
+    )
     parser.add_argument(
         "--case",
         choices=[name for name, _func in SMOKE_CASES],
@@ -8920,6 +8925,10 @@ def main(argv: list[str] | None = None) -> int:
         help="Run only the named smoke case. Can be passed multiple times.",
     )
     args = parser.parse_args(argv)
+    if args.list:
+        for name, _func in SMOKE_CASES:
+            print(name)
+        return 0
     selected = set(args.case or [])
     report = SmokeReport()
     for name, func in SMOKE_CASES: