Desktop installer fixes (#7174)

# Description of Changes

* Adds a `windows-11-arm` CI/release leg (NSIS, Microsoft JDK 25,
updater keys); JPDFium natives deliberately excluded
(`jpdfiumPlatforms=none`) until published, so don't ship ARM64
installers to users yet
* Defaults `WEBKIT_DISABLE_DMABUF_RENDERER=1` on Linux (crash switching
tools on NVIDIA)
* Strips the bundled libwayland from AppImages (blank window on Fedora
Wayland)
* Blocks off-app webview navigation + window drop guard + close failsafe
(drag-drop bricks the app)
* 120s startup grace before the backend is declared unhealthy, restart
success only announced after a real health check ("Backend stopped
unexpectedly" spam and likely the OAuth port churn)
* Verified: green `windows-arm64` build (234 MB NSIS artifact) and green
Linux run with libwayland confirmed stripped
* JPDFium fixes for multi threading issues
---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have run `task check` to verify linters, typechecks, and tests
pass
- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#7-testing)
for more details.

app/common/build.gradle

@@ -36,18 +36,24 @@ dependencies {
 
     api "com.stirling:jpdfium:${jpdfiumVersion}"
 
-    // -PjpdfiumPlatforms=all|<csv of linux-x64,linux-arm64,darwin-x64,darwin-arm64,windows-x64>
+    // -PjpdfiumPlatforms=all|none|<csv of linux-x64,linux-arm64,darwin-x64,darwin-arm64,windows-x64>
+    // 'none' skips natives entirely (windows-arm64 builds, until JPDFium ships that platform).
     def jpdfiumPlatformsProp = (project.findProperty('jpdfiumPlatforms') ?: 'all').toString().trim()
     def jpdfiumAllPlatforms = ['linux-x64', 'linux-arm64', 'darwin-x64', 'darwin-arm64', 'windows-x64']
-    def jpdfiumPlatforms = jpdfiumPlatformsProp == 'all'
-            ? jpdfiumAllPlatforms
-            : jpdfiumPlatformsProp.split(',').collect { it.trim() }.findAll { it }
+    def jpdfiumPlatforms
+    if (jpdfiumPlatformsProp == 'all') {
+        jpdfiumPlatforms = jpdfiumAllPlatforms
+    } else if (jpdfiumPlatformsProp == 'none') {
+        jpdfiumPlatforms = []
+    } else {
+        jpdfiumPlatforms = jpdfiumPlatformsProp.split(',').collect { it.trim() }.findAll { it }
+    }
     def jpdfiumInvalid = jpdfiumPlatforms.findAll { !jpdfiumAllPlatforms.contains(it) }
     if (jpdfiumInvalid) {
         throw new GradleException("Unknown jpdfiumPlatforms value(s): ${jpdfiumInvalid.join(', ')}. " +
-                "Valid: ${jpdfiumAllPlatforms.join(', ')} or 'all'.")
+                "Valid: ${jpdfiumAllPlatforms.join(', ')}, 'all' or 'none'.")
     }
-    logger.lifecycle("JPDFium native platforms: ${jpdfiumPlatforms.join(', ')}")
+    logger.lifecycle("JPDFium native platforms: ${jpdfiumPlatforms ? jpdfiumPlatforms.join(', ') : 'none'}")
     jpdfiumPlatforms.each { platform ->
         runtimeOnly "com.stirling:jpdfium-natives-${platform}:${jpdfiumVersion}"
     }