Clean up Dockerfile: use absolute output path, remove unused user setup

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -7,14 +7,10 @@ COPY go.mod go.sum ./
 RUN go mod download
 COPY . .
 RUN CGO_ENABLED=0 go build -trimpath -ldflags="-s -w -X main.version=${VERSION}" \
-    -o mc-proxy ./cmd/mc-proxy
+    -o /mc-proxy ./cmd/mc-proxy
 
 FROM alpine:3.21
 
-RUN addgroup -S mc-proxy && adduser -S mc-proxy -G mc-proxy
-
-COPY --from=builder /build/mc-proxy /usr/local/bin/mc-proxy
-
-USER mc-proxy
+COPY --from=builder /mc-proxy /usr/local/bin/mc-proxy
 ENTRYPOINT ["mc-proxy"]
 CMD ["server", "--config", "/srv/mc-proxy/mc-proxy.toml"]