Harden + scaffold: FastAPI/Celery/Postgres/Redis dynamic-pricing skeleton

[MacFall7]

Summary

Greenfield scaffold of an authority-separated Shopify dynamic-pricing service. Pricing engine proposes, merchant policy gates, Shopify client executes, audit trail records. Guardrails are constructor inputs, not exception handlers. Rollback reads back through the append-only price_events table.

9 commits, ~1,800 LOC across 47 new files. Do NOT merge before reviewing the README narrative against the engineering — they should match.

Pre-merge checklist

Hygiene

• Working-tree secrets scan clean — only legitimate field/argument names (shopify_api_key, sentry_dsn, secret: str) match (api_key|secret|password|token|dsn|bearer); no actual secret values
• Brand/operator-language scan clean — zero matches for claude|anthropic|cowork|lovable|ai-generated|gpt|gemini|last updated|voice match|audit-defensible|operator note|justin|krishnamurthy
• .env.example placeholders only (your-shopify-api-key-here, change-me)
• .gitignore covers .env, *.db, __pycache__, .venv, node_modules, dist, .idea, .vscode, .DS_Store, *.log

License + attribution

• LICENSE: MIT, Copyright (c) 2026 Mac McFall / M87 Studio
• backend/app/__init__.py author block in place
• frontend/package.json author and repository.url set (uses current repo name E-Commerce; GitHub redirect will handle post-rename)

README rewrite

• Authority-separation framing (engine → policy → Shopify → audit)
• Plain markdown headers, no emoji, no marketing language
• "Known limitations" table is honest about the Shopify-client stub, the frontend stub, the toy pricing signal, and the missing API auth
• Stack table, architecture diagram, design notes, quick-start, tests subsection, roadmap pointer, MIT footer

Tests / migrations / CI

• backend/tests/test_smoke.py — 3 tests (health, root, X-Process-Time header)
• backend/tests/test_pricing_engine.py — 8 tests covering cost floor, merchant min/max, max-change-pct caps (up + down), new-product protection, neutral-signal no-op, suggestion-id uniqueness
• backend/tests/test_policy.py — 4 tests covering auto-apply window, manual-review hold, large-delta reject, no-change approval
• backend/alembic/versions/0001_initial_schema.py — hand-written baseline for merchants, products, price_events (no live DB available to autogenerate against)
• .github/workflows/ci.yml — ruff + pytest on backend, vite build on frontend, runs on push to main and on PR

Items NOT in this PR (your hand-off)

• Repo rename e-commerce → ecom-dynamic-pricing (Settings → Rename — keyword surface matters for recruiter search)
• Repo description: FastAPI + Celery + Postgres + Redis SaaS skeleton for Shopify dynamic pricing with guardrails, rollback, and audit trail.
• Topics: fastapi celery postgres redis shopify saas marketplace dynamic-pricing python react typescript docker
• Visibility flip if private
• Profile pin on github.com/MacFall7

Test plan

• cd backend && pip install -r requirements-dev.txt && pytest — expect 15 tests pass
• cd backend && ruff check . — expect clean
• cp .env.example .env && docker compose up --build — api on :8000, worker running, alembic migrations apply on startup
• curl http://localhost:8000/health/ready — Postgres + Redis both report ok
• cd frontend && npm install && npm run build — vite build succeeds
• Read TECHNICAL_DEBT.md against backend/app/shopify/client.py — confirm the stub is documented as a stub and the cutover plan is reachable

---

Generated by Claude Code