feat: add ARM64 Linux build target and download detection (#427)

- CI: add ubuntu-24.04-arm matrix entry with aarch64-unknown-linux-gnu
- Node sidecar: download linux-arm64 Node.js bundle for ARM runners
- Download API: add linux-appimage-arm64 pattern for aarch64 AppImage
- Download banner: show both x64 and ARM64 Linux options (UA can't distinguish)
- Desktop updater: map Linux aarch64 to linux-appimage-arm64 for in-app updates
- Smoke test: fix AppImage search path for cross-target builds

.github/workflows/build-desktop.yml

@@ -55,6 +55,11 @@ jobs:
             node_target: 'x86_64-unknown-linux-gnu'
             label: 'Linux-x64'
             timeout: 120
+          - platform: 'ubuntu-24.04-arm'
+            args: '--target aarch64-unknown-linux-gnu'
+            node_target: 'aarch64-unknown-linux-gnu'
+            label: 'Linux-ARM64'
+            timeout: 120
 
     runs-on: ${{ matrix.platform }}
     name: Build (${{ matrix.label }})
@@ -77,7 +82,7 @@ jobs:
         uses: dtolnay/rust-toolchain@631a55b12751854ce901bb631d5902ceb48146f7
         with:
           toolchain: stable
-          targets: ${{ contains(matrix.platform, 'macos') && 'aarch64-apple-darwin,x86_64-apple-darwin' || '' }}
+          targets: ${{ contains(matrix.platform, 'macos') && 'aarch64-apple-darwin,x86_64-apple-darwin' || (matrix.label == 'Linux-ARM64' && 'aarch64-unknown-linux-gnu' || '') }}
 
       - name: Rust cache
         uses: swatinem/rust-cache@ad397744b0d591a723ab90405b7247fac0e6b8db
@@ -298,7 +303,7 @@ jobs:
         shell: bash
         run: |
           sudo apt-get install -y xvfb imagemagick
-          APPIMAGE=$(find src-tauri/target/release/bundle/appimage -name '*.AppImage' | head -1)
+          APPIMAGE=$(find src-tauri/target -path '*/bundle/appimage/*.AppImage' | head -1)
           if [ -z "$APPIMAGE" ]; then
             echo "::error::No AppImage found after build"
             exit 1

api/download.js

@@ -10,6 +10,7 @@ const PLATFORM_PATTERNS = {
   'macos-arm64': (name) => name.endsWith('_aarch64.dmg'),
   'macos-x64': (name) => name.endsWith('_x64.dmg') && !name.includes('setup'),
   'linux-appimage': (name) => name.endsWith('_amd64.AppImage'),
+  'linux-appimage-arm64': (name) => name.endsWith('_aarch64.AppImage'),
 };
 
 const VARIANT_IDENTIFIERS = {

scripts/download-node.sh

@@ -15,6 +15,7 @@ Supported targets:
   - x86_64-apple-darwin
   - aarch64-apple-darwin
   - x86_64-unknown-linux-gnu
+  - aarch64-unknown-linux-gnu
 
 Environment:
   NODE_VERSION   Node.js version to bundle (default: 22.14.0)
@@ -72,7 +73,14 @@ if [[ -z "${TARGET}" ]]; then
         esac
         ;;
       Linux)
-        TARGET="x86_64-unknown-linux-gnu"
+        case "${RUNNER_ARCH:-}" in
+          ARM64|arm64)
+            TARGET="aarch64-unknown-linux-gnu"
+            ;;
+          *)
+            TARGET="x86_64-unknown-linux-gnu"
+            ;;
+        esac
         ;;
       *)
         echo "Unsupported RUNNER_OS: ${RUNNER_OS}" >&2
@@ -96,7 +104,14 @@ if [[ -z "${TARGET}" ]]; then
         esac
         ;;
       Linux)
-        TARGET="x86_64-unknown-linux-gnu"
+        case "$(uname -m)" in
+          aarch64|arm64)
+            TARGET="aarch64-unknown-linux-gnu"
+            ;;
+          *)
+            TARGET="x86_64-unknown-linux-gnu"
+            ;;
+        esac
         ;;
       MINGW*|MSYS*|CYGWIN*|Windows_NT)
         TARGET="x86_64-pc-windows-msvc"
@@ -135,6 +150,12 @@ case "${TARGET}" in
     NODE_RELATIVE_PATH="bin/node"
     OUTPUT_NAME="node"
     ;;
+  aarch64-unknown-linux-gnu)
+    DIST_NAME="node-v${NODE_VERSION}-linux-arm64"
+    ARCHIVE_NAME="${DIST_NAME}.tar.gz"
+    NODE_RELATIVE_PATH="bin/node"
+    OUTPUT_NAME="node"
+    ;;
   *)
     echo "Unsupported target: ${TARGET}" >&2
     exit 1

src/app/desktop-updater.ts

@@ -134,7 +134,9 @@ export class DesktopUpdater implements AppModule {
     }
 
     if (normalizedOs === 'linux') {
-      return normalizedArch === 'x86_64' ? 'linux-appimage' : null;
+      if (normalizedArch === 'x86_64') return 'linux-appimage';
+      if (normalizedArch === 'aarch64') return 'linux-appimage-arm64';
+      return null;
     }
 
     return null;

src/components/DownloadBanner.ts

@@ -31,7 +31,7 @@ function dismiss(panel: HTMLElement, fromDownload = false): void {
   panel.addEventListener('transitionend', () => panel.remove(), { once: true });
 }
 
-type Platform = 'macos-arm64' | 'macos-x64' | 'macos' | 'windows' | 'linux' | 'unknown';
+type Platform = 'macos-arm64' | 'macos-x64' | 'macos' | 'windows' | 'linux' | 'linux-x64' | 'linux-arm64' | 'unknown';
 
 function detectPlatform(): Platform {
   const ua = navigator.userAgent;
@@ -64,7 +64,8 @@ function allButtons(): DlButton[] {
     { cls: 'mac', href: '/api/download?platform=macos-arm64', label: `\uF8FF ${t('modals.downloadBanner.macSilicon')}` },
     { cls: 'mac', href: '/api/download?platform=macos-x64', label: `\uF8FF ${t('modals.downloadBanner.macIntel')}` },
     { cls: 'win', href: '/api/download?platform=windows-exe', label: `\u229E ${t('modals.downloadBanner.windows')}` },
-    { cls: 'linux', href: '/api/download?platform=linux-appimage', label: `\u{1F427} ${t('modals.downloadBanner.linux')}` },
+    { cls: 'linux', href: '/api/download?platform=linux-appimage', label: `\u{1F427} ${t('modals.downloadBanner.linux')} (x64)` },
+    { cls: 'linux', href: '/api/download?platform=linux-appimage-arm64', label: `\u{1F427} ${t('modals.downloadBanner.linux')} (ARM64)` },
   ];
 }
 
@@ -76,6 +77,8 @@ function buttonsForPlatform(p: Platform): DlButton[] {
     case 'macos': return buttons.filter(b => b.cls === 'mac');
     case 'windows': return buttons.filter(b => b.cls === 'win');
     case 'linux': return buttons.filter(b => b.cls === 'linux');
+    case 'linux-x64': return buttons.filter(b => b.href.includes('linux-appimage') && !b.href.includes('arm64'));
+    case 'linux-arm64': return buttons.filter(b => b.href.includes('linux-appimage-arm64'));
     default: return buttons;
   }
 }