feat(app): implement Product Scan review flow, dynamic batch expiry picker, custom PDFs, PO relationships, and aligned card layouts

backend/CLAUDE.md

@@ -56,7 +56,7 @@ node pfm-web-app/scripts/accuracy-check.mts
 Python services (uv-managed, same as `ai-ocr-pfm-2026` — see `AGENTS.md`):
 ```bash
 ./scripts/install.sh            # bootstrap .venv for vLLM server
-./scripts/install-pipeline.sh   # bootstrap .venv-api — currently missing ultralytics/torch, see plans/next-enhancements.md task 2.1
+./scripts/install-pipeline.sh   # bootstrap .venv-api
 ./scripts/serve.sh              # vLLM genai server on :8118
 ./scripts/serve-pipeline.sh     # pipeline API on :8090 + classify_ocr_server.py on :8120
 ```