[BACKEND] Initialize Go backend structure and dependencies (#23)

server/Dockerfile

@@ -1,5 +1,8 @@
 # ==========================================
-# Chat Switchboard Backend Dockerfile
+# Chat Switchboard - Backend Dockerfile
+# ==========================================
+# Standalone Go API server for cluster deployment.
+# Build context is ./server (not repo root).
 # ==========================================
 
 # Build stage
@@ -7,16 +10,14 @@ FROM golang:1.22-bookworm AS builder
 
 WORKDIR /app
 
-# Copy go mod files first for caching
-# Build context is ./server, so paths are relative to that
-COPY go.mod go.sum ./
+# Copy module files and download deps
+COPY go.mod go.sum* ./
 RUN go mod download
 
-# Copy source code from server directory
+# Copy source and tidy (resolves any go.sum gaps)
 COPY . .
-
-# Build the application
-RUN CGO_ENABLED=1 go build -o /bin/engine .
+RUN go mod tidy
+RUN CGO_ENABLED=0 go build -ldflags="-s -w" -o /bin/switchboard .
 
 # Runtime stage
 FROM debian:bookworm-slim
@@ -25,11 +26,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
     && rm -rf /var/lib/apt/lists/*
 
-COPY --from=builder /bin/engine /usr/local/bin/engine
+COPY --from=builder /bin/switchboard /usr/local/bin/switchboard
 
-WORKDIR /app
+EXPOSE 8080
 
-VOLUME ["/app/data"]
-
-ENTRYPOINT ["engine"]
-CMD ["serve"]
+ENTRYPOINT ["switchboard"]