Add Telebit client wrapper

Dockerfile.client

@@ -0,0 +1,21 @@
+FROM golang:1.24-alpine AS builder
+
+ARG TELEBIT_REF=master
+ARG TARGETOS=linux
+ARG TARGETARCH=amd64
+
+RUN apk add --no-cache git
+
+WORKDIR /src
+RUN git clone --depth 1 --branch "${TELEBIT_REF}" https://github.com/therootcompany/telebit.git .
+
+RUN go generate -mod=vendor ./...
+
+# The upstream vendored x/net revision does not build on current macOS toolchains.
+RUN go get golang.org/x/net@v0.40.0
+
+RUN CGO_ENABLED=0 GOOS="${TARGETOS}" GOARCH="${TARGETARCH}" go build -mod=mod -o /out/telebit ./cmd/telebit
+RUN CGO_ENABLED=0 GOOS="${TARGETOS}" GOARCH="${TARGETARCH}" go build -mod=mod -o /out/signjwt ./cmd/signjwt
+
+FROM scratch AS export
+COPY --from=builder /out/ /