feat: add build-linux.sh for Linux AMD64 packaging

- Add build-linux.sh script for end-to-end Linux builds
- Add build-linux.sh to MANIFEST.in for source distribution inclusion
- Fix all build scripts to handle sys.path when run directly

MANIFEST.in

@@ -8,6 +8,7 @@ include pyproject.toml
 include UmbraEdit.py
 include pkgutils.py
 include run_tests.py
+include build-linux.sh
 
 include setup/macos/*
 include setup/windows/*

build-linux.sh

@@ -0,0 +1,204 @@
+#!/usr/bin/env bash
+# UmbraEdit Linux Build Script
+# Builds .deb package and AppImage from source tarball
+#
+# Usage:
+#   chmod +x build-linux.sh
+#   ./build-linux.sh
+#
+set -euo pipefail
+
+# Colors for output
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m' # No Color
+
+echo "=========================================="
+echo "UmbraEdit Linux Build Script"
+echo "=========================================="
+
+# Detect architecture
+ARCH=$(uname -m)
+echo "Detected architecture: $ARCH"
+
+if [[ "$ARCH" != "x86_64" && "$ARCH" != "aarch64" ]]; then
+    echo -e "${RED}Error: Unsupported architecture: $ARCH${NC}"
+    echo "Supported architectures: x86_64, aarch64"
+    exit 1
+fi
+
+# Detect Linux distribution
+if [ -f /etc/os-release ]; then
+    . /etc/os-release
+    DISTRO=$ID
+    VERSION=$VERSION_ID
+else
+    echo -e "${RED}Error: Cannot detect Linux distribution${NC}"
+    exit 1
+fi
+
+echo "Detected distribution: $DISTRO $VERSION"
+
+# ---------------------------------------------------------
+# Step 1: Install build dependencies
+# ---------------------------------------------------------
+echo ""
+echo "=========================================="
+echo "Step 1: Installing build dependencies"
+echo "=========================================="
+
+if command -v apt-get &> /dev/null; then
+    sudo apt-get update
+    sudo apt-get install -y \
+        python3 \
+        python3-pip \
+        python3-pyqt6 \
+        python3-pyqt6.qtsvg \
+        python3-enchant \
+        qt6-image-formats-plugins \
+        qt6-svg-plugins \
+        dh-python \
+        debhelper \
+        python3-build \
+        python3-setuptools \
+        appimagetool \
+        file
+elif command -v dnf &> /dev/null; then
+    sudo dnf install -y \
+        python3 \
+        python3-pip \
+        python3-pyqt6 \
+        python3-enchant \
+        qt6-qtimageformats \
+        qt6-qtsvg \
+        python3-build \
+        python3-setuptools \
+        appimagetool
+elif command -v pacman &> /dev/null; then
+    sudo pacman -Sy --noconfirm \
+        python \
+        python-pip \
+        python-pyqt6 \
+        python-enchant \
+        qt6-imageformats \
+        qt6-qtsvg \
+        python-build \
+        python3-setuptools \
+        appimagetool
+else
+    echo -e "${RED}Error: Unsupported package manager${NC}"
+    echo "Please install manually: python3, pyqt6, pyenchant, dpkg-buildpackage, appimagetool"
+    exit 1
+fi
+
+# ---------------------------------------------------------
+# Step 2: Extract source tarball
+# ---------------------------------------------------------
+echo ""
+echo "=========================================="
+echo "Step 2: Extracting source tarball"
+echo "=========================================="
+
+TARBALL="umbraedit-2026.11.5.tar.gz"
+
+if [ ! -f "$TARBALL" ]; then
+    echo -e "${RED}Error: $TARBALL not found in current directory${NC}"
+    echo "Download it from: https://git.umbratools.com/umbragit/UmbraEdit/-/releases/v2026.11.0006"
+    exit 1
+fi
+
+echo "Extracting $TARBALL..."
+tar xzf "$TARBALL"
+cd umbraedit-2026.11.5
+
+echo "Extracted to: $(pwd)"
+
+# ---------------------------------------------------------
+# Step 3: Install Python dependencies
+# ---------------------------------------------------------
+echo ""
+echo "=========================================="
+echo "Step 3: Installing Python dependencies"
+echo "=========================================="
+
+python3 -m pip install --user --upgrade pip setuptools wheel
+python3 -m pip install --user -r <(python3 utils/main.py gen-req --groups app)
+
+# ---------------------------------------------------------
+# Step 4: Build .deb package (Debian/Ubuntu only)
+# ---------------------------------------------------------
+if [ "$DISTRO" = "ubuntu" ] || [ "$DISTRO" = "debian" ]; then
+    echo ""
+    echo "=========================================="
+    echo "Step 4: Building .deb package"
+    echo "=========================================="
+
+    python3 utils/build_debian.py --distro "$DISTRO" --build 1
+
+    echo ""
+    echo -e "${GREEN}Build complete!${NC}"
+    echo "Debian package: dist_deb/umbraedit_*.deb"
+    echo ""
+    echo "To install:"
+    echo "  sudo dpkg -i dist_deb/umbraedit_*_${ARCH}.deb"
+else
+    echo ""
+    echo "=========================================="
+    echo "Step 4: Skipping .deb build (not Debian/Ubuntu)"
+    echo "=========================================="
+fi
+
+# ---------------------------------------------------------
+# Step 5: Build AppImage
+# ---------------------------------------------------------
+echo ""
+echo "=========================================="
+echo "Step 5: Building AppImage"
+echo "=========================================="
+
+python3 utils/build_appimage.py --linux manylinux_2_28 --arch "$ARCH" --python 3.12
+
+echo ""
+echo -e "${GREEN}Build complete!${NC}"
+echo "AppImage: dist_appimage/umbraedit-2026.11-${ARCH}.AppImage"
+echo ""
+echo "To run:"
+echo "  chmod +x dist_appimage/umbraedit-2026.11-${ARCH}.AppImage"
+echo "  ./dist_appimage/umbraedit-2026.11-${ARCH}.AppImage"
+
+# ---------------------------------------------------------
+# Step 6: Build Python wheel (optional, for pip install)
+# ---------------------------------------------------------
+echo ""
+echo "=========================================="
+echo "Step 6: Building Python wheel"
+echo "=========================================="
+
+python3 -m pip install --user build
+python3 -m build --wheel
+
+echo ""
+echo -e "${GREEN}Wheel built:${NC}"
+echo "  dist/umbraedit-2026.11.1-py3-none-any.whl"
+echo ""
+echo "To install:"
+echo "  pip install dist/umbraedit-2026.11.1-py3-none-any.whl"
+
+# ---------------------------------------------------------
+# Done
+# ---------------------------------------------------------
+echo ""
+echo "=========================================="
+echo "Build complete!"
+echo "=========================================="
+echo ""
+echo "Build artifacts:"
+ls -la dist_deb/ 2>/dev/null || true
+ls -la dist_appimage/ 2>/dev/null || true
+ls -la dist/ 2>/dev/null || true
+echo ""
+echo "To run UmbraEdit:"
+echo "  From AppImage: ./dist_appimage/umbraedit-2026.11-${ARCH}.AppImage"
+echo "  From .deb:     sudo dpkg -i dist_deb/umbraedit_*_${ARCH}.deb && umbraedit"
+echo "  From wheel:    pip install dist/umbraedit-2026.11.1-py3-none-any.whl && umbraedit"