Initial commit: EatMe attendance tracker

Google-SSO PWA for bistro employee clock-in/out, admin employee
management, and stats with CSV export. Express + SQLite backend,
React + Zustand frontend in the light-mono-tui design language.
Multi-stage Dockerfile, compose.yaml for image-based deploys, nginx
reverse-proxy template, and an OKF documentation bundle in docs/.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/architecture/overview.md

@@ -0,0 +1,51 @@
+---
+type: Architecture Overview
+title: System overview
+description: How the EatMe frontend, backend, and database fit together.
+tags: [architecture, backend, frontend]
+timestamp: 2026-08-12T00:00:00Z
+---
+
+# System overview
+
+EatMe is a small monorepo with two independently-runnable apps that ship as
+one Docker image in production.
+
+- **`backend/`** — Express + TypeScript API, SQLite via `better-sqlite3`
+  (entry point `backend/src/index.ts`). Owns all state: employee whitelist,
+  attendance events, sessions.
+- **`frontend/`** — Vite + React + TypeScript PWA (entry point
+  `frontend/src/App.tsx`). Talks to the backend only over `/api/*`; in dev,
+  Vite proxies that path to `http://localhost:4000` (see
+  `frontend/vite.config.ts`).
+
+## Request flow
+
+1. Employee/admin signs in with Google Identity Services in the browser
+   (ID-token flow, no server-side OAuth redirect) — see
+   [Auth flow](./auth-flow.md).
+2. The frontend POSTs the Google ID token to `POST /api/auth/google`; the
+   backend verifies it, issues its own JWT session cookie, and from then on
+   every `/api/*` call rides on that cookie (`credentials: 'include'` in
+   `frontend/src/api/client.ts`).
+3. All app logic (fetching, polling, derived state) lives in Zustand stores
+   under `frontend/src/store/` — see [Frontend](/docs/frontend/index.md).
+   Components are thin consumers of store selectors/actions.
+4. In production the backend also serves the built frontend as static files
+   (`dist/public/`, see [Deployment](./deployment.md)) — one process, one
+   container, one origin.
+
+## Design language
+
+The UI follows the "light monochrome TUI" style defined at
+`~/doc/concepts/ui/light-mono-tui.md`: grey page background, black type and
+1px borders, mono font, inverted fills for active/hover state, no accent
+colors, no border-radius. Implemented as plain CSS tokens in
+`frontend/src/styles/tui.css`.
+
+## Related
+
+- [Auth flow](./auth-flow.md)
+- [Deployment](./deployment.md)
+- [Data model](/docs/data-model/index.md)
+- [API](/docs/api/index.md)