fix: merge script now writes to current directory for volume compatibility

Changed merge_jsonl.py to use os.getcwd() instead of os.path.dirname(__file__)
to ensure merged.jsonl is written to the working directory where data files exist,
not to the script's installation directory.

Root cause:
- Dockerfile copies scripts to /app/scripts/ for volume compatibility
- entrypoint.sh runs: cd /app/data && python /app/scripts/merge_jsonl.py
- Old logic used script directory (/app/scripts/), ignoring working directory
- This caused merged.jsonl to be created in /app/scripts/ instead of /app/data/
- Since /app/data/ is volume-mounted, merged file was not visible to host

Solution:
- Scripts now respect current working directory (Unix philosophy)
- Works correctly with volume mounts and script relocation
- Tested in both local and Docker directory structure scenarios

Fixes the issue where merged.jsonl was missing from mounted data volume.

data/merge_jsonl.py

@@ -18,7 +18,8 @@ all_nasdaq_100_symbols = [
 ]
 
 # 合并所有以 daily_price 开头的 json，逐文件一行写入 merged.jsonl
-current_dir = os.path.dirname(__file__)
+# Use current working directory instead of script directory for volume compatibility
+current_dir = os.getcwd()
 pattern = os.path.join(current_dir, 'daily_price*.json')
 files = sorted(glob.glob(pattern))