Linux support (#381)

* Add desktop release CI and support for Arch Linux packaging

* Make Gradle wrapper executable in desktop-release workflow

* Make Gradle wrapper executable in desktop-release workflow

* Make Gradle wrapper executable in desktop-release workflow

* Configure Gradle and update Java environment in desktop-release workflow

* Update Java setup and AUR packaging in desktop release workflow

* Update Java setup and AUR packaging in desktop release workflow

* Add MSIX packaging support for Windows desktop distribution

* Update AUR packaging metadata and validation

* Use spine toc attribute for NCX resolution

* crash fixes

* Implement automatic discovery and injection of EPUB font face siblings

* Enhance custom font support with family grouping and variable font handling

* Optimize metadata loading and improve TTS highlighting

* Add keyboard navigation support for EPUB reader

* Refine PDF spread page sizing to respect aspect ratios

* Implement responsive maximum height for reader popups and sheets

* Handle TTS generation failures by skipping problematic chunks

* Refactor PDF tile rendering logic and zoom indicator behavior

* Prefer block and offset locators over page index in native vertical flow

* Implement save and share actions for original book files

* Add Estonian language support

* Implement temporary viewing mode for external files

* Implement direct opening for temporary external files without library persistence

* fix failing tests

* Import SharedFileCapabilities in DesktopLibraryUi

* Improve native vertical reader progress, persistence, and image support

* Center target in viewport for native vertical reader and support animated scrolling

scripts/desktop/publish-pdfium-release.ps1

@@ -0,0 +1,51 @@
+param(
+    [string]$Repository = $env:GITHUB_REPOSITORY,
+    [string]$Tag = "pdfium-desktop-v1",
+    [string]$Title = "Desktop Pdfium binaries",
+    [string]$PdfiumRoot = "third_party/pdfium"
+)
+
+if ([string]::IsNullOrWhiteSpace($Repository)) {
+    throw "Repository is required. Pass -Repository owner/repo or set GITHUB_REPOSITORY."
+}
+
+$ErrorActionPreference = "Stop"
+
+$folders = @(
+    @{ Directory = "linux-x64-v8"; Asset = "pdfium-linux-x64-v8.zip" },
+    @{ Directory = "win-x64-v8"; Asset = "pdfium-win-x64-v8.zip" }
+)
+
+$workDir = Join-Path ([System.IO.Path]::GetTempPath()) ("reader-pdfium-release-" + [System.Guid]::NewGuid().ToString("N"))
+New-Item -ItemType Directory -Force -Path $workDir | Out-Null
+
+try {
+    foreach ($folder in $folders) {
+        $source = Join-Path $PdfiumRoot $folder.Directory
+        if (-not (Test-Path $source)) {
+            throw "Missing Pdfium folder: $source"
+        }
+
+        $assetPath = Join-Path $workDir $folder.Asset
+        Compress-Archive -Force -Path $source -DestinationPath $assetPath
+    }
+
+    $previousErrorActionPreference = $ErrorActionPreference
+    $ErrorActionPreference = "Continue"
+    gh release view $Tag --repo $Repository *> $null
+    $releaseExists = $LASTEXITCODE -eq 0
+    $ErrorActionPreference = $previousErrorActionPreference
+
+    if (-not $releaseExists) {
+        gh release create $Tag --repo $Repository --title $Title --notes "Pdfium binaries used by desktop CI packaging."
+    }
+
+    foreach ($folder in $folders) {
+        $assetPath = Join-Path $workDir $folder.Asset
+        gh release upload $Tag $assetPath --repo $Repository --clobber
+    }
+} finally {
+    if (Test-Path $workDir) {
+        Remove-Item -Recurse -Force $workDir
+    }
+}