Add OpenRouter chat provider; fix Windows load errors (0.17.0).

- OpenRouter as an alternative chat provider: server-side API key
  (settings.json or OPENROUTER_API_KEY), model list with vision marks and
  filter, SSE streaming, images as data URLs. Memory embeddings stay on Ollama;
  park/warm LLM are no-ops for the remote provider.
- AssistentSaveKnowledgeAttach: JArray param is not supported by SwarmUI API
  reflection and aborted registration of every later API call; use string[].
- SQLite bootstrap: preload native e_sqlite3 for the current OS/arch
  (win/osx/linux) and resolve DllImport to it.
- settings.json: shared-read + atomic write with retry to avoid Windows
  sharing violations.
- csproj: fix MSB4012 in the native SQLite copy target.

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

SwarmAssistentExtension.csproj

@@ -29,7 +29,7 @@
                 Condition="$([System.String]::Copy('%(RuntimeCopyLocalItems.DestinationSubPath)').Contains('e_sqlite3'))" />
         </ItemGroup>
         <Copy SourceFiles="@(_SqliteNative)"
-            DestinationFiles="$(OutputPath)@(_SqliteNative->'%(RuntimeCopyLocalItems.DestinationSubPath)')"
+            DestinationFiles="@(_SqliteNative->'$(OutputPath)%(DestinationSubPath)')"
             SkipUnchangedFiles="true"
             Condition="'@(_SqliteNative)' != ''" />
         <Copy SourceFiles="@(_SqliteNative)"