[appimage] AppImage auf jeder Linux-Distro lauffaehig (inkl. NixOS)

Zwei kombinierte Patches:

1. main.rs: WEBKIT_DISABLE_DMABUF_RENDERER + WEBKIT_DISABLE_COMPOSITING_MODE
   als defensive Defaults wenn nicht vom User gesetzt. Behebt typische
   WebKit2GTK-Renderer-Crashes auf modernen Wayland-Setups.

2. Workflow: nach 'tauri build' wird der AppRun gepatched.
   - Detect NixOS via /run/opengl-driver/lib -> Host-Mesa via LD_LIBRARY_PATH
   - WebKit-Workarounds als ENV-Defaults (override moeglich)
   - Standard linuxdeploy-Pfade (PATH, XDG_DATA_DIRS etc.)
   - Re-bundle mit appimagetool

Resultat: AppImage laeuft out-of-the-box auf Debian/Ubuntu/Fedora/NixOS,
ohne dass der User ENV-Vars setzen muss.

.forgejo/workflows/build-appimage.yml

@@ -36,6 +36,59 @@ jobs:
           npm run tauri build -- --bundles appimage
           ls -la src-tauri/target/release/bundle/appimage/
 
+      - name: Patch AppRun fuer NixOS-Support + Re-Bundle
+        run: |
+          set -e
+          BUNDLE_DIR=src-tauri/target/release/bundle/appimage
+          APPDIR=$(ls -d "$BUNDLE_DIR"/*.AppDir | head -1)
+          OLD_APPIMAGE=$(ls "$BUNDLE_DIR"/*.AppImage | head -1)
+          OLD_NAME=$(basename "$OLD_APPIMAGE")
+
+          echo "AppDir: $APPDIR"
+          echo "Original AppImage: $OLD_NAME"
+
+          # Original AppRun sichern (falls Tauri spaeter mehr reinpackt)
+          cp "$APPDIR/AppRun" "$APPDIR/AppRun.original"
+
+          # Custom AppRun: NixOS-Detection + WebKit-Workarounds
+          cat > "$APPDIR/AppRun" << 'APPRUN_EOF'
+          #!/bin/bash
+          HERE="$(dirname "$(readlink -f "${0}")")"
+
+          # NixOS: Host-Mesa unter /run/opengl-driver bevorzugen,
+          # weil bundled Mesa gegen NixOS-Treiber kollidiert
+          if [ -d /run/opengl-driver/lib ]; then
+            export LD_LIBRARY_PATH="/run/opengl-driver/lib:${LD_LIBRARY_PATH}"
+          fi
+
+          # WebKit-Workarounds fuer problematische GPU/Compositor-Stacks.
+          # Nur setzen wenn User nichts vorgegeben hat (override moeglich).
+          : "${WEBKIT_DISABLE_DMABUF_RENDERER:=1}"
+          : "${WEBKIT_DISABLE_COMPOSITING_MODE:=1}"
+          export WEBKIT_DISABLE_DMABUF_RENDERER WEBKIT_DISABLE_COMPOSITING_MODE
+
+          # Standard-AppImage-Runtime (analog zu linuxdeploy-Default)
+          export PATH="${HERE}/usr/bin:${PATH}"
+          export LD_LIBRARY_PATH="${HERE}/usr/lib:${LD_LIBRARY_PATH}"
+          export XDG_DATA_DIRS="${HERE}/usr/share:${XDG_DATA_DIRS:-/usr/local/share:/usr/share}"
+          export GSETTINGS_SCHEMA_DIR="${HERE}/usr/share/glib-2.0/schemas:${GSETTINGS_SCHEMA_DIR}"
+          export GDK_PIXBUF_MODULE_FILE="${HERE}/usr/lib/gdk-pixbuf-2.0/2.10.0/loaders.cache"
+
+          # Tauri-Binary aufrufen
+          BIN=$(find "${HERE}/usr/bin" -maxdepth 1 -type f -executable | head -1)
+          exec "$BIN" "$@"
+          APPRUN_EOF
+          chmod +x "$APPDIR/AppRun"
+
+          echo "--- neuer AppRun ---"
+          cat "$APPDIR/AppRun"
+
+          # Altes AppImage weg, neu packen mit appimagetool
+          rm "$OLD_APPIMAGE"
+          appimagetool --no-appstream "$APPDIR" "$BUNDLE_DIR/$OLD_NAME"
+
+          ls -la "$BUNDLE_DIR/"
+
       - name: Get Version
         id: version
         run: |

src-tauri/src/main.rs

@@ -2,5 +2,21 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
 
 fn main() {
+    // WebKit-Workarounds fuer Linux-GPU-Stacks die mit dem
+    // bundled WebKit2GTK Probleme machen (NixOS, aeltere Mesa,
+    // Wayland-Bugs). Nur setzen wenn der User nicht selbst
+    // schon was vorgegeben hat.
+    #[cfg(target_os = "linux")]
+    {
+        for (key, val) in [
+            ("WEBKIT_DISABLE_DMABUF_RENDERER", "1"),
+            ("WEBKIT_DISABLE_COMPOSITING_MODE", "1"),
+        ] {
+            if std::env::var_os(key).is_none() {
+                std::env::set_var(key, val);
+            }
+        }
+    }
+
     claude_desktop_lib::run()
 }