- config.py: resolve_data_path (legacy abs + rel) + rel_data_path
- all file-opening reads wrapped: preview, autolabel, training, model
download, live count, projects.get; training_start_point hack replaced
- new writes store paths relative to data/
- legacy stale rows (/home/asus/reTraining/...) resolve without migration
- requirements: REQ-187 added; REQ-188 (per-class max box) + REQ-186
copy-line amendment drafted for the next task