added rust server

BalanceServer/Dockerfile

@@ -1,14 +1,17 @@
-FROM golang:1.25.12-alpine AS build
+FROM rust:1.90-bookworm AS build
 WORKDIR /src
-COPY go.mod go.sum* ./
-RUN go mod download
-COPY . .
-RUN CGO_ENABLED=0 go build -trimpath -ldflags="-s -w" -o /out/balance-server ./cmd/balance-server
+COPY Cargo.toml Cargo.lock ./
+COPY src ./src
+COPY internal/httpapi/web ./internal/httpapi/web
+RUN cargo build --locked --release
 
-FROM alpine:3.22
-RUN addgroup -S balance && adduser -S -G balance balance && mkdir /data && chown balance:balance /data
+FROM debian:bookworm-slim
+# Keep the original Alpine image's numeric identity so existing volumes remain writable.
+RUN groupadd --system --gid 101 balance \
+    && useradd --system --uid 100 --gid balance --home-dir /nonexistent --no-log-init balance \
+    && mkdir /data && chown balance:balance /data
+COPY --from=build /src/target/release/balance-server /usr/local/bin/balance-server
 USER balance
-COPY --from=build /out/balance-server /usr/local/bin/balance-server
 ENV BALANCE_ADDR=:8080 BALANCE_DB_PATH=/data/balance.db
 EXPOSE 8080
 VOLUME ["/data"]