feat: add Docker support with Dockerfile, docker-compose.yml, and .dockerignore

Dockerfile

@@ -0,0 +1,51 @@
+FROM node:25-alpine3.22 AS frontend-builder
+
+WORKDIR /app/frontend
+
+COPY frontend/package.json frontend/package-lock.json* ./
+
+RUN npm ci
+
+COPY frontend/ .
+
+COPY frontend/.env.production .env
+
+RUN npm run build
+
+FROM golang:1.25.4-alpine3.22 AS backend-builder
+
+WORKDIR /app
+
+RUN go install github.com/swaggo/swag/cmd/swag@latest
+
+COPY backend/go.mod backend/go.sum ./
+
+RUN go mod download
+
+COPY backend .
+
+RUN swag init
+
+RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o garage-ui .
+
+FROM alpine:3.22
+
+WORKDIR /app
+
+RUN apk --no-cache add ca-certificates wget
+
+RUN addgroup -g 1000 garageui && \
+    adduser -D -u 1000 -G garageui garageui
+
+COPY --from=backend-builder --chown=garageui:garageui /app/garage-ui .
+COPY --from=frontend-builder /app/frontend/dist ./frontend/dist
+
+USER garageui
+
+EXPOSE 8080
+
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+  CMD wget --no-verbose --tries=1 --spider http://localhost:8080/health || exit 1
+
+CMD ["./garage-ui"]
+