Add multi-platform build scripts

- build-rpm.sh: Build RPM packages on RHEL/CentOS/Fedora
- build-alpine.sh: Build APK packages on Alpine Linux
- build-arch.sh: Build Arch packages on Arch Linux/Manjaro

Each script can also run in Docker containers for cross-platform builds.
Complements CI/CD pipeline for local package building.

build-rpm.sh

@@ -0,0 +1,50 @@
+#!/bin/bash
+# Build RPM Package for RHEL/CentOS/Fedora
+# Run on: RHEL 8/9, CentOS 8/9, Fedora 38+
+
+set -e
+
+echo "=== Linux Patch API - RPM Build Script ==="
+echo ""
+
+# Check if running on RPM-based system
+if ! command -v rpmbuild &> /dev/null; then
+    echo "Installing RPM build tools..."
+    if command -v dnf &> /dev/null; then
+        sudo dnf install -y rpm-build cargo rust gcc systemd-devel
+    elif command -v yum &> /dev/null; then
+        sudo yum install -y rpm-build cargo rust gcc systemd-devel
+    else
+        echo "Error: Cannot install rpm-build. Please install manually."
+        exit 1
+    fi
+fi
+
+# Setup RPM build directory structure
+mkdir -p ~/rpmbuild/{BUILD,BUILDROOT,RPMS,SOURCES,SPECS,SRPMS}
+
+# Copy source files
+echo "Preparing source files..."
+cp linux-patch-api.spec ~/rpmbuild/SPECS/
+cp -r target/release/linux-patch-api ~/rpmbuild/SOURCES/ 2>/dev/null || cargo build --release
+cp -r configs ~/rpmbuild/SOURCES/
+cp -r debian ~/rpmbuild/SOURCES/
+
+# Build RPM
+echo "Building RPM package..."
+rpmbuild -ba ~/rpmbuild/SPECS/linux-patch-api.spec
+
+# Copy to releases directory
+echo ""
+echo "Copying package to releases/..."
+mkdir -p releases
+cp ~/rpmbuild/RPMS/x86_64/*.rpm releases/
+
+echo ""
+echo "=== Build Complete ==="
+echo "Package: releases/linux-patch-api-*.rpm"
+echo ""
+echo "Install with:"
+echo "  sudo dnf install -y ./releases/linux-patch-api-*.rpm"
+echo "  # or"
+echo "  sudo yum install -y ./releases/linux-patch-api-*.rpm"