Persist the repo status snapshot for faster resumability

Constraint: Future sessions benefit from a saved machine-readable snapshot, not just on-demand script output
Rejected: Keep snapshot stdout-only | Makes handoff less durable and harder to automate across sessions
Confidence: high
Scope-risk: narrow
Directive: Refresh .omx/latest_status_snapshot.json whenever the default docs, smoke paths, or next-step commands materially change
Tested: /usr/local/miniconda3/bin/python scripts/status_snapshot.py --output .omx/latest_status_snapshot.json; JSON parse check for latest_commit and next_commands
Not-tested: External automation consuming the saved snapshot over multiple sessions

@@ -10,7 +10,7 @@ Use this checklist when a new session starts working on the repo.
 ## 2. Verify repo health
 ```bash
 git status --short
-/usr/local/miniconda3/bin/python scripts/status_snapshot.py
+/usr/local/miniconda3/bin/python scripts/status_snapshot.py --output .omx/latest_status_snapshot.json
 ```
 
 ## 3. Verify open-dataset tooling

 #!/usr/bin/env python3
+import argparse
 import json
 import subprocess
 from pathlib import Path
@@ -9,7 +10,8 @@ workspace_root = root.parent
 def sh(cmd):
     return subprocess.check_output(cmd, shell=True, text=True).strip()
 
-snapshot = {
+def build_snapshot():
+    return {
         'latest_commit': sh('git log --oneline -n 1'),
         'docs': {
             'readme': str((workspace_root / 'docs/README.md').resolve()),
@@ -31,5 +33,22 @@ snapshot = {
             'inspect_jamendo': '/usr/local/miniconda3/bin/python src/data/external_adapters.py inspect-local mtg_jamendo data/raw/mtg_jamendo_audio --eval-ratio 0.2 --query-duration 8.0',
             'smoke_jamendo': '/usr/local/miniconda3/bin/python src/data/external_adapters.py smoke-local mtg_jamendo data/raw/mtg_jamendo_audio --output-root data/external_smoke --eval-ratio 0.2 --query-duration 8.0 --train-epochs 1 --batch-size 2'
         }
-}
-print(json.dumps(snapshot, ensure_ascii=False, indent=2))
+    }
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--output', default=None)
+    args = parser.parse_args()
+
+    snapshot = build_snapshot()
+    text = json.dumps(snapshot, ensure_ascii=False, indent=2)
+    if args.output:
+        out = Path(args.output)
+        out.parent.mkdir(parents=True, exist_ok=True)
+        out.write_text(text)
+    print(text)
+
+
+if __name__ == '__main__':
+    main()

@@ -202,6 +202,25 @@
 - 新 session 现在不只靠静态文档，也可以直接读取当前仓库状态快照
 - 持续开发交接更稳
 
+### Stage: 状态快照落盘
+
+完成项：
+- 扩展 [acr-engine/scripts/status_snapshot.py](../acr-engine/scripts/status_snapshot.py)
+- 新增 `--output`
+- 可直接写入 `.omx/latest_status_snapshot.json`
+
+验证结果：
+- `/usr/local/miniconda3/bin/python scripts/status_snapshot.py --output .omx/latest_status_snapshot.json` 成功
+- 已验证：
+  - 文件存在
+  - JSON 可解析
+  - 包含 `latest_commit`
+  - 包含 `next_commands`
+
+结论：
+- 新 session 现在可以直接读取最近一次状态快照文件
+- 交接信息更适合自动化和长期持续开发
+
 ### Stage: confused 定向优化 v6（sample-level weighting）
 
 完成项：

@@ -276,6 +276,7 @@
    - [docs/session-handoff.md](./session-handoff.md)
    - [acr-engine/FIRST_RUN_CHECKLIST.md](../acr-engine/FIRST_RUN_CHECKLIST.md)
    - 运行 [acr-engine/scripts/status_snapshot.py](../acr-engine/scripts/status_snapshot.py)
+   - 或直接查看最新落盘快照：`acr-engine/.omx/latest_status_snapshot.json`
 
 2. 检查真实数据是否已落位：
    - `acr-engine/data/raw/fma_small_audio/`