Fix Docker build context

.dockerignore

@@ -2,5 +2,4 @@
 bin
 dist
 config.json
-mqqt-scrubber
 docs/All connections.json

Dockerfile

@@ -5,7 +5,10 @@ WORKDIR /src
 COPY go.mod go.sum ./
 RUN go mod download
 
-COPY . .
+COPY cmd ./cmd
+COPY internal ./internal
+COPY config.example.json ./config.example.json
+RUN test -f ./cmd/mqqt-scrubber/main.go || (echo "cmd/mqqt-scrubber/main.go is missing from the Docker build context; verify the checkout, sparse-checkout settings, and build context path" >&2; exit 1)
 RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o /out/mqqt-scrubber ./cmd/mqqt-scrubber
 
 FROM alpine:3.20

docker-compose.yml

@@ -1,5 +1,3 @@
-version: "3.8"
-
 services:
   mqqt-scrubber:
     build: