Bundle native libraries into the single-file publish

PublishSingleFile alone still left e_sqlite3.dll as a loose file next
to PrepStep.exe; moving just the exe (e.g. copying it elsewhere) broke
SQLite with an opaque SqliteConnection type initializer exception.
IncludeNativeLibrariesForSelfExtract embeds it in the exe instead,
self-extracted to a temp folder at first run, so the published exe is
a genuinely single, movable file.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

PrepStep/PrepStep.csproj

@@ -8,12 +8,11 @@
     <ImplicitUsings>enable</ImplicitUsings>
     <ApplicationHighDpiMode>PerMonitorV2</ApplicationHighDpiMode>
     <ApplicationIcon>app.ico</ApplicationIcon>
-    <!-- Nome tecnico (cartella/csproj/namespace) e nome del file .exe pubblicato: PrepStep.
-         Il nome prodotto mostrato all'utente ("Cevolani StepPrep") resta separato, sotto. -->
     <AssemblyTitle>Cevolani StepPrep</AssemblyTitle>
     <Product>Cevolani StepPrep</Product>
     <Company>Cevolani</Company>
     <Version>0.1.0</Version>
+    <IncludeNativeLibrariesForSelfExtract>true</IncludeNativeLibrariesForSelfExtract>
   </PropertyGroup>
 
   <ItemGroup>