Refactor kafka to pure Go (franz-go), fix DBC stubs, update Dockerfile

services/gateway/Dockerfile

@@ -1,27 +1,44 @@
-ARG BASE_IMAGE=cloud_base_go
-FROM ${BASE_IMAGE} as builder-go
+# syntax=docker/dockerfile:1
 
-WORKDIR /build/gateway_go
+# Build stage
+FROM golang:1.25-alpine AS builder
 
-COPY ./gateway_go/go.mod ./gateway_go/go.sum ./
-RUN go mod edit -replace fiskerinc.com/modules=../fiskerinc.com/modules \
-    && go mod download
+RUN apk add --no-cache git ca-certificates tzdata
 
-COPY ./gateway_go ./
-RUN go mod edit -replace fiskerinc.com/modules=../fiskerinc.com/modules \
-    && go build -tags musl
+WORKDIR /app
 
-FROM alpine:3.17
+# Copy go.work and module files for dependency caching
+COPY go.work ./
+COPY pkg/go.mod pkg/go.sum ./pkg/
+COPY pkg/can-go/go.mod pkg/can-go/go.sum ./pkg/can-go/
+COPY services/gateway/go.mod services/gateway/go.sum ./services/gateway/
 
-RUN apk add --no-cache librdkafka --repository=https://dl-cdn.alpinelinux.org/alpine/edge/community \
-  && apk add --no-cache ca-certificates
+# Download dependencies (cached layer)
+RUN --mount=type=cache,target=/go/pkg/mod \
+    go mod download -x
 
-COPY ./modules_go/logger/log_config .
-ENV LOG_CONFIG=log_config
+# Copy source
+COPY pkg/ ./pkg/
+COPY services/gateway/ ./services/gateway/
 
-COPY ./gateway_go/docs ./docs
-COPY --from=builder-go /build/gateway_go/gateway .
+# Build static binary
+WORKDIR /app/services/gateway
+RUN --mount=type=cache,target=/go/pkg/mod \
+    --mount=type=cache,target=/root/.cache/go-build \
+    CGO_ENABLED=0 GOOS=linux GOARCH=amd64 \
+    go build -ldflags="-s -w" -trimpath -o /gateway .
 
-EXPOSE 8077
+# Runtime stage - distroless for minimal attack surface
+FROM gcr.io/distroless/static-debian12:nonroot
 
-CMD ./gateway
+COPY --from=builder /gateway /gateway
+COPY --from=builder /app/services/gateway/docs /docs
+COPY --from=builder /app/pkg/logger/log_config /log_config
+COPY --from=builder /usr/share/zoneinfo /usr/share/zoneinfo
+
+ENV LOG_CONFIG=/log_config
+ENV TZ=UTC
+
+EXPOSE 8077 11011
+
+ENTRYPOINT ["/gateway"]