feat: add Docker setup with Dockerfile and docker-compose

Co-authored-by: aider (openai/gpt-5) <aider@aider.chat>

Dockerfile

@@ -0,0 +1,44 @@
+# Multi-stage build for Rust Linux container
+FROM rust:1.82-bookworm AS builder
+
+# Build dependencies (libudev for serialport on Linux)
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    pkg-config \
+    libudev-dev \
+    build-essential \
+    ca-certificates \
+    tzdata \
+ && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+# Leverage docker layer caching for dependencies
+COPY Cargo.toml Cargo.lock ./
+RUN mkdir -p src && echo 'fn main() { println!("cargo:rerun-if-changed=build.rs"); }' > src/main.rs
+RUN cargo build --release || true
+RUN rm -rf src
+
+# Copy full source and build real binaries
+COPY . .
+RUN cargo build --release --bin ntp_timeturner --bin ptp_probe
+
+# Runtime image
+FROM debian:bookworm-slim AS runtime
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    libudev1 \
+    ca-certificates \
+    tzdata \
+ && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+COPY --from=builder /app/target/release/ntp_timeturner /usr/local/bin/ntp_timeturner
+COPY --from=builder /app/target/release/ptp_probe /usr/local/bin/ptp_probe
+COPY static ./static
+
+ENV RUST_LOG=info
+EXPOSE 8080
+
+# Default to running the main server
+CMD ["ntp_timeturner"]