[codex] Add task workspaces and human review workbench

[zhouxuan3550]

Summary

• Add task workspaces so each run has isolated output files and a config snapshot.
• Add a human review workbench for terminology, translation, subtitle rows, and TTS text.
• Split Streamlit processing into review-aware checkpoints and update batch processing to use per-task workspaces.

Impact

• Reduces cross-run output/config pollution.
• Gives long-video workflows human confirmation points before translation, subtitle generation, and dubbing.
• Preserves existing JSON, Excel, and SRT artifacts while adding backups and review status metadata.

Test Plan

• /Users/oliverchow/VideoLingo/.venv/bin/python -m unittest discover -s tests -v
• /Users/oliverchow/VideoLingo/.venv/bin/python -m compileall -q core batch st.py
• Streamlit smoke test on http://localhost:8765 returned 200