Adds a new "openWebUi" integration kind (under a new "ai" category) and an
AI Chat widget for chatting with models served by Open WebUI.
- Integration: Bearer API key auth, model list, native chat history CRUD, and
token-by-token streaming chat completions (SSE).
- Widget: in-input model picker, streaming responses, and an in-widget history
panel. Reconstructs conversations from Open WebUI's message tree with a flat
fallback.
- Streaming is delivered over the WebSocket subscription link.
- Adds integration and widget documentation.