Add Ubuntu PPA packaging support (#47)

Adds Ubuntu PPA packaging with automated GitHub Actions workflow.

- Debian packaging files in debian/ directory
- GitHub Actions workflow for automated PPA uploads
- Targets Ubuntu Questing (25.10) with Rust 1.88

scripts/test-deb-build.sh

@@ -0,0 +1,66 @@
+#!/bin/bash
+set -e
+
+UBUNTU_RELEASE=${1:-noble}
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_DIR="$(dirname "$SCRIPT_DIR")"
+
+echo "Testing Debian package build for Ubuntu $UBUNTU_RELEASE"
+echo "=================================================="
+
+# Build the Docker container
+docker build -t rustnet-deb-test:$UBUNTU_RELEASE -f - "$PROJECT_DIR" <<EOF
+FROM ubuntu:$UBUNTU_RELEASE
+
+# Install build dependencies
+RUN apt-get update && apt-get install -y \\
+    debhelper \\
+    devscripts \\
+    dpkg-dev \\
+    rustup \\
+    libpcap-dev \\
+    libelf-dev \\
+    elfutils \\
+    zlib1g-dev \\
+    clang \\
+    llvm \\
+    pkg-config \\
+    lintian \\
+    file
+
+WORKDIR /build
+COPY . /build/
+
+# Build the source package
+RUN echo "Building source package..." && \\
+    debuild -S -sa -d -us -uc
+
+# Build the binary package (simulates what Launchpad does)
+RUN echo "Building binary package..." && \\
+    cd .. && \\
+    dpkg-source -x rustnet-monitor_*.dsc extracted && \\
+    cd extracted && \\
+    dpkg-buildpackage -b -uc -us
+
+# List the built packages
+RUN echo "Built packages:" && \\
+    ls -lh /build/../*.deb || true
+
+# Run lintian on the package
+RUN echo "Running lintian checks..." && \\
+    lintian /build/../*.deb || true
+
+# Test the package contents
+RUN echo "Package contents:" && \\
+    dpkg-deb -c /build/../rustnet_*.deb
+
+CMD ["/bin/bash"]
+EOF
+
+echo ""
+echo "Build completed successfully!"
+echo ""
+echo "To extract the .deb file, run:"
+echo "  docker create --name rustnet-deb-extract rustnet-deb-test:$UBUNTU_RELEASE"
+echo "  docker cp rustnet-deb-extract:/build/../rustnet_*.deb ."
+echo "  docker rm rustnet-deb-extract"