feat: implement multi-stage Dockerfile for deployment infrastructure

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

Dockerfile

@@ -0,0 +1,38 @@
+# Builder stage
+FROM golang:1.26-alpine AS builder
+
+WORKDIR /app
+
+# Copy go.mod and go.sum
+COPY go.mod go.sum ./
+
+# Download dependencies
+RUN go mod download
+
+# Copy source code
+COPY . .
+
+# Build api and cron binaries
+RUN go build -o api ./cmd/api
+RUN go build -o cron ./cmd/cron
+
+# Runtime stage
+FROM alpine:latest
+
+WORKDIR /app
+
+# Copy binaries from builder
+COPY --from=builder /app/api /app/api
+COPY --from=builder /app/cron /app/cron
+
+# Set environment variables
+ENV DB_DSN="postgres://postgres:postgres@postgres:5432/trip_planner?sslmode=disable"
+ENV REDIS_ADDR="redis:6379"
+ENV YANDEX_API_KEY=""
+ENV TRIP_PLANNER_ADMIN_API_KEY=""
+
+# Expose port
+EXPOSE 8080
+
+# Set entrypoint for api service (default)
+ENTRYPOINT ["/app/api"]