修复策划V2不可变文件失败残留

失败时清理已创建的空文件或截断文件

保留已有文件的幂等与内容冲突校验

apps/ai-game-creator-shell/src-tauri/src/agent/runtime_protocol/planning_policy_v2.rs

@@ -839,13 +839,24 @@ fn create_v2_immutable_file(root: &Path, relative: &str, bytes: &[u8]) -> Result
         .open(&path)
     {
         Ok(mut file) => {
-            harden_new_game_creator_private_path(&path, false, "Planning V2 文件")?;
-            file.write_all(bytes)
-                .and_then(|_| file.sync_data())
-                .map_err(|error| {
-                    format!("写入 Planning V2 文件失败：{}: {error}", path.display())
-                })?;
-            Ok(())
+            // `create_new` has already made the final path visible. Every
+            // subsequent step must therefore be transactional from the
+            // caller's perspective: a failed ACL repair, partial write, or
+            // failed sync must not leave an empty/truncated immutable file
+            // that would permanently block a retry.
+            let result = (|| {
+                harden_new_game_creator_private_path(&path, false, "Planning V2 文件")?;
+                file.write_all(bytes)
+                    .and_then(|_| file.sync_data())
+                    .map_err(|error| {
+                        format!("写入 Planning V2 文件失败：{}: {error}", path.display())
+                    })?;
+                Ok(())
+            })();
+            if result.is_err() {
+                let _ = fs::remove_file(&path);
+            }
+            result
         }
         Err(error) if error.kind() == std::io::ErrorKind::AlreadyExists => {
             prepare_game_creator_private_path_for_read(&path, false, "Planning V2 文件")?;