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>

Assets/assistent.css

@@ -1110,6 +1110,15 @@
     opacity: 0.8;
 }
 
+.sa-openrouter-box {
+    display: grid;
+    gap: 0.45rem;
+}
+
+.sa-openrouter-box[hidden] {
+    display: none;
+}
+
 .sa-danger-btn {
     color: #e06c75 !important;
 }