fix: use --appimage-extract instead of unsquashfs to unpack linuxdeploy

The squashfs magic was not found at any 512-byte boundary because
Tauri's linuxdeploy build uses a non-standard layout. Using the
AppImage's own --appimage-extract flag extracts squashfs internally
without FUSE or needing to locate the offset manually.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitea/workflows/release.yml

@@ -163,18 +163,18 @@ jobs:
 
       - name: Stage AppRun and linuxdeploy for AppImage bundler
         run: |
-          set -ex
+          set -e
           mkdir -p ~/.cache/tauri
-          ls tools/
           cp tools/AppRun-x86_64 ~/.cache/tauri/AppRun-x86_64
           chmod +x ~/.cache/tauri/AppRun-x86_64
 
-          wget \
+          wget -q \
             "https://github.com/tauri-apps/binary-releases/releases/download/linuxdeploy/linuxdeploy-x86_64.AppImage" \
             -O /tmp/linuxdeploy.AppImage
+          chmod +x /tmp/linuxdeploy.AppImage
 
-          OFFSET=$(python3 -c "d=open('/tmp/linuxdeploy.AppImage','rb').read();o=[i for i in range(0,len(d),512) if d[i:i+4] in (b'hsqs',b'sqsh')];print(o[0]) if o else exit(1)")
+          (cd /tmp && /tmp/linuxdeploy.AppImage --appimage-extract)
-          unsquashfs -d /tmp/linuxdeploy-root -offset "$OFFSET" /tmp/linuxdeploy.AppImage
+          mv /tmp/squashfs-root /tmp/linuxdeploy-root
 
           gcc -o ~/.cache/tauri/linuxdeploy-x86_64.AppImage tools/ld_wrapper.c
           chmod +x ~/.cache/tauri/linuxdeploy-x86_64.AppImage