fix(record): surface detailed recording errors and hardware hints to the GUI

[robertchoi]

Description

This PR resolves the issue where a recording session fails (e.g., due to camera disconnect, servo overload, or serial connection loss) but the leLab GUI silently redirects the user to the /upload page without showing any error trace or diagnostic guide.

We now extract the raw exception from the recording worker, map it to a user-friendly troubleshooting hint (reusing the logic from Inference), halt status polling, and render a dedicated failure AlertDialog on the frontend.

Related Issues

Closes #78

Key Changes

1. Shared Hardware Troubleshooting Utility

• Moved _friendly_hint helper from lelab/rollout.py to lelab/utils/devices.py as a public friendly_hint() function. This enables both inference (rollout) and recording status handlers to share the same troubleshooting guidance for common hardware bugs (gripper overload, port busy, frame timeouts, etc.).

2. Backend (FastAPI status endpoint)

• Surfaced Error & Hint: Updated handle_recording_status() in lelab/record.py to return the error and mapped hint if current_phase == "error". The error is pulled from the last_recording_info structure populated by the recording worker's exception catcher.

3. Frontend (React + Vite)

• Halted Polling: Intercepted the "error" phase in frontend/src/pages/Recording.tsx during the status polling effect. When detected, it sets a local sessionError state and halts polling, preventing the automatic navigation redirect to /upload.
• Failure AlertDialog: Rendered an AlertDialog containing the exact error trace and the friendly hardware hint, offering a clear "Return to Home" button to recover gracefully.

4. Tests

• Updated imports in tests/test_rollout.py for the moved friendly_hint.
• Added a unit test test_recording_status_surfaces_error_and_hint in tests/test_record.py to ensure correct serialization of errors and hints.

---

Verification Results

Automated Tests

Ran the pytest suites in the local virtual environment:

.venv\Scripts\pytest tests/test_rollout.py tests/test_record.py

[Copilot]

Pull request overview

Surfaces recording failures and hardware troubleshooting hints in the GUI, alongside unrelated camera, visualization, and documentation changes.

Changes:

• Shares hardware-error hints between recording and inference.
• Stops polling and displays recording failures in an alert dialog.
• Adds tests, camera naming changes, Korean guides, and a teleoperation adjustment.

Reviewed changes

Copilot reviewed 10 out of 11 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
lelab/utils/devices.py	Adds shared troubleshooting hints.
lelab/rollout.py	Uses the shared hint utility.
lelab/record.py	Returns recording errors and hints.
frontend/src/pages/Recording.tsx	Displays recording failure details.
tests/test_rollout.py	Updates hint utility tests.
tests/test_record.py	Tests recording error status.
lelab/teleoperate.py	Disables URDF angle corrections.
lelab/server.py	Adds Chrome-oriented Linux camera names.
study/install.md	Adds a Korean Windows installation guide.
study/day0_overview.md	Adds a Korean project overview.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.