v1.19 — Bug fixes, Hungarian accents, better error handling

- Fix: Back button was always visible (ternary always returned Visible)
- Fix: Missing Hungarian accents on EditionPage ("Válasszon kiadást")
- Fix: Better ODT download error messages (network/timeout distinguished)
- Signed with Azure Trusted Signing (Microsoft root CA, instant SmartScreen trust)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

InstaSoftOfficeTool.csproj

@@ -9,9 +9,9 @@
     <Company>InstaSoft Zrt.</Company>
     <Product>InstaSoft Office Tool</Product>
     <Copyright>Copyright (c) InstaSoft Zrt. 2026</Copyright>
-    <Version>1.1.7</Version>
-    <AssemblyVersion>1.1.7.0</AssemblyVersion>
-    <FileVersion>1.1.7.0</FileVersion>
+    <Version>1.1.9</Version>
+    <AssemblyVersion>1.1.9.0</AssemblyVersion>
+    <FileVersion>1.1.9.0</FileVersion>
     <ApplicationManifest>app.manifest</ApplicationManifest>
     <LangVersion>latest</LangVersion>
   </PropertyGroup>