Add DigiByte and Dash mainnet bitcoin-family RPC nodes.

DigiByte uses a tarball-install digibyted.Dockerfile (v9.26.3); Dash uses
dashpay/dashd:23.1.7. Both follow the dogecoind bitcoind pattern for RPC
auth, ZMQ, traefik, and x-upstreams wiring.

Co-authored-by: Cursor <cursoragent@cursor.com>

digibyte/digibyted.Dockerfile

@@ -0,0 +1,24 @@
+# digibyted — official release tarball (no Docker image upstream).
+ARG VERSION=9.26.3
+
+FROM debian:stable-slim
+
+ARG VERSION
+ARG SHA256=51465a7a7409dc9a734e463b8fd95fb9773033753d79504de946ab2a0aa0991c
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    ca-certificates \
+    curl \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /tmp
+RUN curl -fsSL -o digibyte.tar.gz \
+    "https://github.com/DigiByte-Core/digibyte/releases/download/v${VERSION}/digibyte-${VERSION}-x86_64-linux-gnu.tar.gz" \
+    && echo "${SHA256}  digibyte.tar.gz" | sha256sum -c - \
+    && tar xzf digibyte.tar.gz \
+    && cp "digibyte-${VERSION}/bin/digibyted" "digibyte-${VERSION}/bin/digibyte-cli" /usr/local/bin/ \
+    && rm -rf /tmp/*
+
+EXPOSE 8545 12024
+
+ENTRYPOINT ["digibyted"]