Initial commit: clean project structure

- Backend: FastAPI + SQLAlchemy + Celery (Python 3.11+)
- Frontend: Vue 3 + TypeScript + Pinia + Tailwind
- Admin Frontend: separate Vue 3 app for management
- Docker Compose: 9 services orchestration
- Specs: design prototypes, memory system PRD, product roadmap

Cleanup performed:
- Removed temporary debug scripts from backend root
- Removed deprecated admin_app.py (embedded UI)
- Removed duplicate docs from admin-frontend
- Updated .gitignore for Vite cache and egg-info

frontend/postcss.config.js

@@ -0,0 +1,6 @@
+export default {
+  plugins: {
+    tailwindcss: {},
+    autoprefixer: {},
+  },
+}