feat: add VAM SFT mini training (T2A Stage 1)

feat: add VLM SFT mini configs, resume training, dataset streaming, and eval fixes

refactor: rename VLM configs, add VLM SFT configs, and improve model loading

reorganize configs into subdirs lm/vlm/vam, remove runs/, add interview docs for pretrain & full_sft

cleanup: remove deprecated doc files, update src training utils

Add local training logger that writes to {save_dir}/{save_weight}.log

Flatten src layout: drop omni namespace, modules live directly under src/