Add run-emulator.sh for one-command QEMU launch

Builds the emulator image if needed and launches it with the right
QEMU flags so it boots straight into the AsteroidOS watch UI. Detects
the best available display backend (GTK or SDL with virgl), enables
KVM when possible, and forwards SSH to localhost:2222.

Usage: ./run-emulator.sh

Author: blin

run-emulator.sh

@@ -0,0 +1,175 @@
+#!/bin/bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+BUILD_DIR="${SCRIPT_DIR}/build"
+DEPLOY_DIR="${BUILD_DIR}/tmp/deploy/images/emulator"
+OE_INIT="${SCRIPT_DIR}/src/oe-core/oe-init-build-env"
+
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m'
+
+info()  { echo -e "${GREEN}[emulator]${NC} $*"; }
+warn()  { echo -e "${YELLOW}[emulator]${NC} $*"; }
+error() { echo -e "${RED}[emulator]${NC} $*" >&2; }
+
+usage() {
+    echo "Usage: $0 [--build|--launch|--help]"
+    echo ""
+    echo "  (no args)   Build image if not found, then launch emulator"
+    echo "  --build     Force rebuild the image, then launch"
+    echo "  --launch    Launch only (skip build, image must exist)"
+    echo "  --help      Show this help"
+    echo ""
+    echo "SSH access:   ssh -p 2222 root@127.0.0.1"
+    exit 0
+}
+
+find_image() {
+    if [ ! -d "${DEPLOY_DIR}" ]; then
+        return 1
+    fi
+    ROOTFS=$(ls -t "${DEPLOY_DIR}"/asteroid-image-emulator.rootfs-*.ext4 2>/dev/null | head -1)
+    KERNEL=$(ls -t "${DEPLOY_DIR}"/bzImage 2>/dev/null | head -1)
+    if [ -z "${ROOTFS:-}" ] || [ -z "${KERNEL:-}" ]; then
+        return 1
+    fi
+    return 0
+}
+
+build_image() {
+    info "Building AsteroidOS emulator image..."
+    info "This may take a while on first build."
+
+    if [ ! -f "${OE_INIT}" ]; then
+        error "OE init script not found at ${OE_INIT}"
+        error "Run prepare-build.sh emulator first to fetch sources."
+        exit 1
+    fi
+
+    cd "${SCRIPT_DIR}"
+    bash -c "
+        source '${OE_INIT}' '${BUILD_DIR}' > /dev/null
+        bitbake asteroid-image
+    "
+
+    if ! find_image; then
+        error "Build completed but image artifacts not found in ${DEPLOY_DIR}"
+        exit 1
+    fi
+
+    info "Build complete!"
+    info "  Root FS: ${ROOTFS}"
+    info "  Kernel:  ${KERNEL}"
+}
+
+find_qemu() {
+    if command -v qemu-system-i386 &>/dev/null; then
+        QEMU_BIN="qemu-system-i386"
+    elif [ -x "${BUILD_DIR}/tmp/work/x86_64-linux/qemu-helper-native/1.0/recipe-sysroot-native/usr/bin/qemu-system-i386" ]; then
+        QEMU_BIN="${BUILD_DIR}/tmp/work/x86_64-linux/qemu-helper-native/1.0/recipe-sysroot-native/usr/bin/qemu-system-i386"
+    else
+        error "qemu-system-i386 not found. Install QEMU:"
+        error "  sudo apt install qemu-system-x86  # Debian/Ubuntu"
+        error "  sudo pacman -S qemu-full          # Arch"
+        exit 1
+    fi
+
+    DISPLAY_BACKENDS=$("${QEMU_BIN}" -display help 2>&1 | grep -oP '^\w+' || true)
+    DISPLAY_OPT=""
+    GPU_DEVICE=""
+
+    if echo "${DISPLAY_BACKENDS}" | grep -q '^gtk$'; then
+        DISPLAY_OPT="-display gtk,gl=on,show-cursor=on"
+        GPU_DEVICE="-vga none -device virtio-vga-gl"
+        info "Using GTK display with virgl 3D acceleration"
+    elif echo "${DISPLAY_BACKENDS}" | grep -q '^sdl$'; then
+        DISPLAY_OPT="-display sdl,gl=on"
+        GPU_DEVICE="-vga none -device virtio-vga-gl"
+        info "Using SDL display with virgl 3D acceleration"
+    else
+        warn "No GTK/SDL display backend found, trying fallback..."
+        if "${QEMU_BIN}" -device help 2>&1 | grep -q 'virtio-vga-gl'; then
+            GPU_DEVICE="-vga none -device virtio-vga-gl"
+        elif "${QEMU_BIN}" -device help 2>&1 | grep -q 'virtio-vga'; then
+            GPU_DEVICE="-vga none -device virtio-vga"
+        else
+            GPU_DEVICE="-vga none -device virtio-gpu-pci"
+        fi
+        for backend in gtk sdl spice-app; do
+            if echo "${DISPLAY_BACKENDS}" | grep -q "^${backend}$"; then
+                DISPLAY_OPT="-display ${backend}"
+                break
+            fi
+        done
+        if [ -z "${DISPLAY_OPT}" ]; then
+            error "No graphical display backend available in ${QEMU_BIN}"
+            error "Available backends: ${DISPLAY_BACKENDS}"
+            error "Install QEMU with GTK or SDL support."
+            exit 1
+        fi
+    fi
+
+    KVM_OPT=""
+    if [ -w /dev/kvm ]; then
+        KVM_OPT="-enable-kvm"
+        info "KVM hardware acceleration enabled"
+    else
+        warn "KVM not available (no /dev/kvm or no permission). Emulation will be slower."
+        warn "  To enable: sudo usermod -aG kvm \$USER && newgrp kvm"
+    fi
+}
+
+launch_emulator() {
+    info "Launching AsteroidOS emulator..."
+    info "  Root FS: $(basename "${ROOTFS}")"
+    info "  Kernel:  $(basename "${KERNEL}")"
+    info ""
+    info "  SSH:     ssh -p 2222 root@127.0.0.1"
+    info "  Telnet:  telnet 127.0.0.1 2323"
+    info ""
+    info "Close the QEMU window or press Ctrl+C to stop."
+    echo ""
+
+    exec "${QEMU_BIN}" \
+        -device virtio-net-pci,netdev=net0,mac=52:54:00:12:35:02 \
+        -netdev user,id=net0,hostfwd=tcp:127.0.0.1:2222-:22,hostfwd=tcp:127.0.0.1:2323-:23 \
+        -object rng-random,filename=/dev/urandom,id=rng0 -device virtio-rng-pci,rng=rng0 \
+        -drive file="${ROOTFS}",if=virtio,format=raw,snapshot=on \
+        -usb -device usb-tablet -usb -device usb-kbd \
+        -cpu IvyBridge -machine q35,i8042=off ${KVM_OPT} -smp 4 -m 512 \
+        ${GPU_DEVICE} \
+        ${DISPLAY_OPT} \
+        -kernel "${KERNEL}" \
+        -append "root=/dev/vda rw mem=512M ip=dhcp oprofile.timer=1 tsc=reliable no_timer_check rcupdate.rcu_expedited=1 swiotlb=0"
+}
+
+FORCE_BUILD=false
+LAUNCH_ONLY=false
+
+case "${1:-}" in
+    --build)  FORCE_BUILD=true ;;
+    --launch) LAUNCH_ONLY=true ;;
+    --help|-h) usage ;;
+    "") ;;
+    *) error "Unknown option: $1"; usage ;;
+esac
+
+if [ "${LAUNCH_ONLY}" = true ]; then
+    if ! find_image; then
+        error "No emulator image found. Run without --launch to build first."
+        exit 1
+    fi
+elif [ "${FORCE_BUILD}" = true ] || ! find_image; then
+    if ! find_image; then
+        info "No existing image found, building..."
+    fi
+    build_image
+else
+    info "Using existing image (use --build to force rebuild)"
+fi
+
+find_qemu
+launch_emulator