fix(installer,worker): service hosting, dark theme, uninstall polish

Worker:
- Wire UseWindowsService + Microsoft.Extensions.Hosting.WindowsServices so
  SCM's Service Control Protocol handshake succeeds. Previously the binary
  exited immediately under sc start, leaving the service registered but
  never running.

Installer:
- Pin SDK to .NET 9 (global.json) — SDK 10 dropped win-arm from its RID
  graph, breaking restore of the WPF project; .NET 9 keeps win-arm AND
  understands the .slnx solution format.
- Force SelfContained=true and default RID=win-x64 when PublishSingleFile
  is set, so Rider Publish and CLI produce the same bundle.
- Dark theme: set Background/Foreground explicitly on WizardWindow and
  SettingsWindow roots (WPF implicit styles don't cascade to derived
  Window types). Custom ComboBox template + ComboBoxItem style so
  dropdowns honour the dark palette instead of system defaults.
- Throttle download progress to one report per MB and overwrite the same
  UI line (\r prefix marker) instead of appending per chunk.
- Register ClaudeDo in HKLM\...\Uninstall so it appears in Apps & Features.
  Copy installer into InstallDir\uninstaller\ for the UninstallString, and
  schedule a cmd.exe trampoline to handle the self-delete case when
  Apps & Features launches the copy from inside the install dir.
- Treat sc.exe stop exit 1062 (ERROR_SERVICE_NOT_ACTIVE) as success.
- Delete the uninstall registry key during UninstallRunner.

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

src/ClaudeDo.Installer/ClaudeDo.Installer.csproj

@@ -21,6 +21,8 @@
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(PublishSingleFile)' == 'true'">
+    <SelfContained>true</SelfContained>
+    <RuntimeIdentifier Condition="'$(RuntimeIdentifier)' == ''">win-x64</RuntimeIdentifier>
     <PublishTrimmed>false</PublishTrimmed>
     <IncludeNativeLibrariesForSelfExtract>true</IncludeNativeLibrariesForSelfExtract>
     <IncludeAllContentForSelfExtract>true</IncludeAllContentForSelfExtract>