Rename to gpu-turnstile; swap port roles

The proxy now listens on the standard service ports (Ollama :11434,
ComfyUI :8188) and the actual services move one port up (:11435, :8189).
Metric prefix is now gpu_turnstile_.

Dockerfile

@@ -4,10 +4,10 @@ COPY go.mod ./
 COPY cmd ./cmd
 COPY internal ./internal
 ARG VERSION=dev
-RUN CGO_ENABLED=0 go build -ldflags="-s -w -X main.version=${VERSION}" -o /gpulock ./cmd/gpulock
+RUN CGO_ENABLED=0 go build -ldflags="-s -w -X main.version=${VERSION}" -o /gpu-turnstile ./cmd/gpu-turnstile
 
 FROM gcr.io/distroless/static:nonroot
-COPY --from=build /gpulock /gpulock
-EXPOSE 8189 11435
+COPY --from=build /gpu-turnstile /gpu-turnstile
+EXPOSE 8188 11434
 USER nonroot
-ENTRYPOINT ["/gpulock"]
+ENTRYPOINT ["/gpu-turnstile"]