feat: add Open WebUI AI chat integration and widget

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.

apps/docs/docs/integrations/open-webui/index.mdx

@@ -0,0 +1,39 @@
+---
+title: "Open WebUI"
+description: "Self-hosted AI chat interface for local and remote LLM providers"
+hide_title: true
+---
+
+import { IntegrationHeader } from "@site/src/components/integrations/header";
+import { IntegrationCapabilites } from "@site/src/components/integrations/widgets";
+import { AddingIntegration } from "@site/src/components/integrations/adding";
+import { IntegrationSecrets } from "@site/src/components/integrations/secrets";
+import { openWebUiIntegration } from ".";
+import { openWebUiWidget } from "../../widgets/open-webui";
+
+<IntegrationHeader integration={openWebUiIntegration} categories={["AI", "Chat"]} />
+
+[Open WebUI](https://openwebui.com/) is a self-hosted AI chat interface that aggregates multiple LLM providers (Ollama, OpenAI-compatible APIs, and more) behind a single API. Homarr connects to it so you can chat with your models directly from your dashboard.
+
+### Widgets & Capabilities
+
+<IntegrationCapabilites items={[{ widget: openWebUiWidget }]} />
+
+### Adding the integration
+
+<AddingIntegration />
+
+:::info URL configuration
+Use the root URL of your Open WebUI instance, for example `http://localhost:3000`. Homarr calls the Open WebUI API under `/api` automatically.
+:::
+
+### Secrets
+
+<IntegrationSecrets
+  secrets={[
+    {
+      credentials: ["apiKey"],
+      steps: [],
+    },
+  ]}
+/>

apps/docs/docs/integrations/open-webui/index.ts

@@ -0,0 +1,8 @@
+import { IntegrationDefinition } from "@site/src/types";
+
+export const openWebUiIntegration: IntegrationDefinition = {
+  name: "Open WebUI",
+  description: "Self-hosted AI chat interface for local and remote LLM providers",
+  iconUrl: "https://cdn.jsdelivr.net/gh/homarr-labs/dashboard-icons@master/svg/open-webui.svg",
+  path: "../../integrations/open-webui",
+};

apps/docs/docs/widgets/open-webui/index.mdx

@@ -0,0 +1,47 @@
+---
+title: "AI Chat"
+description: "Chat with AI models through Open WebUI, with model picking and history."
+hide_title: true
+---
+
+import { WidgetHeader } from "@site/src/components/widgets/header";
+import { AddingWidget } from "@site/src/components/widgets/adding";
+import { WidgetConfig } from "@site/src/components/widgets/configuration";
+import { WidgetIntegrations } from "@site/src/components/widgets/integrations";
+import { openWebUiWidget } from ".";
+import { openWebUiIntegration } from "@site/docs/integrations/open-webui";
+
+<WidgetHeader widget={openWebUiWidget} categories={["AI", "Chat"]} />
+
+The AI Chat widget lets you chat with AI models served by Open WebUI directly from your dashboard. Responses stream in token-by-token, you can pick any model your Open WebUI instance exposes (Ollama, OpenAI, and other configured providers), and you can browse and reopen your Open WebUI chat history.
+
+### Supported Integrations
+
+<WidgetIntegrations
+  items={[
+    {
+      integration: openWebUiIntegration,
+    },
+  ]}
+/>
+
+### Adding the widget
+
+<AddingWidget />
+
+### Configuration
+
+<WidgetConfig configuration={openWebUiWidget.configuration} />
+
+### Features
+
+| Feature                 | Description                                                                                                                               |
+| ----------------------- | ----------------------------------------------------------------------------------------------------------------------------------------- |
+| **Model picker**        | Lists every model exposed by Open WebUI's `/api/models` endpoint, selectable from the chat input. The first model is selected by default. |
+| **Streaming responses** | Assistant replies stream in live as they are generated.                                                                                   |
+| **Chat history**        | Browse and reopen previous chats. New conversations are saved back to Open WebUI.                                                         |
+
+### Notes
+
+- The widget uses a single Open WebUI integration.
+- Conversations are stored in Open WebUI itself, under the account that owns the API key, so they also appear in the Open WebUI app.

apps/docs/docs/widgets/open-webui/index.ts

@@ -0,0 +1,25 @@
+import { WidgetDefinition } from "@site/src/types";
+import { IconRobot } from "@tabler/icons-react";
+
+export const openWebUiWidget: WidgetDefinition = {
+  icon: IconRobot,
+  name: "AI Chat",
+  description: "Chat with AI models through Open WebUI, with model picking and history.",
+  path: "../../widgets/open-webui",
+  configuration: {
+    items: [
+      {
+        name: "System prompt",
+        description: "Optional instruction prepended to every conversation.",
+        values: { type: "string" },
+        defaultValue: "empty",
+      },
+      {
+        name: "Show chat history",
+        description: "Show a button to browse and reopen previous Open WebUI chats.",
+        values: { type: "boolean" },
+        defaultValue: "yes",
+      },
+    ],
+  },
+};