fix: phase 5 - Gradio server binding to 0.0.0.0 for Docker compatibility

feat: phase 5 - Gradio UI, visualizer, Dockerfile, docker-compose

feat: phase 4 — FastAPI inference server (schemas, model manager, router, main)

feat: phase 3 - training loop, evaluator, CLI train script

feat: phase 2 - multi-task model (backbone, heads, loss)

feat: phase 1 - data pipeline (utils, transforms, dataset)

chore: scaffold project structure with venv and gitignore