Revert "Revert "fix: disable LoRA export for now" (#308)"

This reverts commit da92f745de.

src/heretic/main.py

@@ -144,13 +144,18 @@ def obtain_merge_strategy(settings: Settings, model: Model) -> str | None:
                     value="merge",
                 ),
                 Choice(
-                title="Save LoRA adapter only (can be merged later)",
-                value="adapter",
+                    title="Cancel",
+                    value="cancel",
                 ),
             ],
         )
 
+        if strategy == "cancel":
+            return None
+
         return strategy
+    else:
+        return "merge"
 
 
 def run():