ops: add docker support

Dockerfile

@@ -0,0 +1,20 @@
+FROM node:23-alpine AS frontend
+WORKDIR /frontend
+COPY frontend/package*.json /frontend
+RUN npm ci
+RUN npm i @tailwindcss/oxide-linux-x64-musl
+COPY frontend/ /frontend
+RUN npm run build
+
+FROM golang:1.24-alpine AS backend
+WORKDIR /backend
+COPY backend/go.* /backend/
+RUN go mod download
+COPY backend/ /backend
+COPY --from=frontend /frontend/dist/client/ /backend/public/
+RUN go build -o HexDeck
+
+FROM scratch
+WORKDIR /app
+COPY --from=backend /backend/HexDeck .
+CMD ["/app/HexDeck"]