publish_model.py: drop the local 'import shutil' that shadowed the module name and broke Gate 5

build/publish_model.py

@@ -261,7 +261,9 @@ def main():
     if not need <= have:
         raise SystemExit(f"{src} is missing {sorted(need - have)} -- nothing to publish")
     if "tokenizer.json" not in have and os.path.exists(os.path.join(a.src, "tokenizer.json")):
-        import shutil
+        # No `import shutil` here: a module-level name re-imported inside this function makes it *local*
+        # to main(), so the verify-only branch's earlier `shutil.rmtree` raised UnboundLocalError and
+        # Gate 5 could never run (found by running it, 2026-09-21T13:40Z).
         shutil.copy(os.path.join(a.src, "tokenizer.json"), src)     # ship the tokenizer that cut the mix
         have.add("tokenizer.json")
     cfg = json.load(open(os.path.join(src, "config.json")))