fix: a reused destination retires the routes pointing at it, and draft_base stays out of diffs

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

backend/windmill-api-scripts/src/scripts.rs

@@ -2426,6 +2426,7 @@ async fn create_script_internal<'c>(
         &w_id,
         &[UserDraftItemKind::Script],
         &ns.path,
+        p_path_opt.as_deref(),
     )
     .await?;
     if p_hashes.is_some() && !p_hashes.unwrap().is_empty() {