整理了初始化过程，现在更容易被继承了。

sync_state_machine/datasource/jsonl/path_utils.py

@@ -0,0 +1,31 @@
+from __future__ import annotations
+
+import logging
+from pathlib import Path
+
+
+logger = logging.getLogger(__name__)
+
+
+def prepare_remote_jsonl_dir(remote_dir: Path, *, project_root: Path) -> Path:
+    project_root_path = project_root.resolve()
+    resolved_remote_dir = remote_dir.resolve(strict=False)
+
+    if resolved_remote_dir.exists():
+        if not resolved_remote_dir.is_dir():
+            raise FileNotFoundError(
+                f"remote_datasource.jsonl_dir exists but is not a directory: {resolved_remote_dir}"
+            )
+        return resolved_remote_dir
+
+    try:
+        resolved_remote_dir.relative_to(project_root_path)
+    except ValueError as exc:
+        raise FileNotFoundError(
+            "remote_datasource.jsonl_dir does not exist and auto-create is only allowed "
+            f"under project root: {resolved_remote_dir} (project_root={project_root_path})"
+        ) from exc
+
+    resolved_remote_dir.mkdir(parents=True, exist_ok=True)
+    logger.info("Created missing remote JSONL directory: %s", resolved_remote_dir)
+    return resolved_remote_dir