fix: Windows JSON patch via node, Linux AppImage via APPIMAGE_EXTRACT_AND_RUN

Windows: ConvertTo-Json outputs True/False (invalid JSON) and UTF-16
BOM, corrupting tauri.conf.json. Switch to `node -e` which round-trips
JSON correctly.

Linux: linuxdeploy is itself an AppImage and cannot execute inside
Docker without FUSE. APPIMAGE_EXTRACT_AND_RUN=1 makes it self-extract
and run as a plain binary instead.

Also fix unreachable_code warning in check_for_update.

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

.gitea/workflows/release.yml

@@ -61,9 +61,7 @@ jobs:
         shell: powershell
         run: |
           $ver = '${{ needs.prepare.outputs.version }}'
-          $d = Get-Content 'src-tauri/tauri.conf.json' -Raw | ConvertFrom-Json
-          $d.version = $ver
-          $d | ConvertTo-Json -Depth 100 | Set-Content 'src-tauri/tauri.conf.json' -Encoding UTF8
+          node -e "const fs=require('fs');const d=JSON.parse(fs.readFileSync('src-tauri/tauri.conf.json','utf8'));d.version='$ver';fs.writeFileSync('src-tauri/tauri.conf.json',JSON.stringify(d,null,2),'utf8');"
 
       - name: Install frontend deps
         shell: powershell
@@ -164,6 +162,7 @@ jobs:
           TAURI_SIGNING_PRIVATE_KEY: ${{ secrets.TAURI_SIGNING_PRIVATE_KEY }}
           TAURI_SIGNING_PRIVATE_KEY_PASSWORD: ''
           NODE_OPTIONS: '--max_old_space_size=4096'
+          APPIMAGE_EXTRACT_AND_RUN: '1'
         run: npm run tauri -- build --bundles appimage,deb
 
       - name: Upload to release

src-tauri/src/lib.rs

@@ -61,14 +61,13 @@ async fn check_for_update(app: tauri::AppHandle) -> Result<UpdateInfo, String> {
     #[cfg(not(any(target_os = "android", target_os = "ios")))]
     {
         use tauri_plugin_updater::UpdaterExt;
-        match app.updater().map_err(|e| e.to_string())?.check().await {
-            Ok(Some(update)) => {
-                return Ok(UpdateInfo { available: true, version: Some(update.version) });
-            }
-            Ok(None) => return Ok(UpdateInfo { available: false, version: None }),
-            Err(e) => return Err(e.to_string()),
-        }
+        return match app.updater().map_err(|e| e.to_string())?.check().await {
+            Ok(Some(update)) => Ok(UpdateInfo { available: true, version: Some(update.version) }),
+            Ok(None) => Ok(UpdateInfo { available: false, version: None }),
+            Err(e) => Err(e.to_string()),
+        };
     }
+    #[cfg(any(target_os = "android", target_os = "ios"))]
     Ok(UpdateInfo { available: false, version: None })
 }