Initial commit: split VNOX monorepo into VNOX-Server

Unified server binary (vnox-serverd) combining:
- Gateway (TCP, auth, channels, sessions, SQLite)
- Voice-node (UDP relay, Opus, jitter buffer)

Standalone gateway (vnox-gateway) and voice-node (vnox-voice-node) preserved as sub-crates.

Dockerfile.voice-node

@@ -0,0 +1,21 @@
+# ─── Stage 1: Build ───────────────────────────────────────────────────────────
+FROM rust:1.85-slim-bookworm AS builder
+
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends \
+        pkg-config libssl-dev libopus-dev cmake && \
+    rm -rf /var/lib/apt/lists/*
+
+WORKDIR /build
+COPY . .
+
+RUN cargo build --release --package vnox-voice-node
+
+# ─── Stage 2: Runtime ─────────────────────────────────────────────────────────
+FROM debian:bookworm-slim
+
+COPY --from=builder /build/target/release/vnox-voice-node /usr/local/bin/vnox-voice-node
+
+EXPOSE 7700/udp
+
+ENTRYPOINT ["vnox-voice-node"]