feat: add assistant widget to demo dashboard

Include the Homarr Assistant widget in the demo board so visitors can
try the assistant directly from the mock/demo dashboard. The widget
renders in its enabled state because demo mode reports the assistant as
available.

apps/nextjs/src/components/assistant/assistant-panel.tsx

@@ -930,7 +930,7 @@ const RequestTelemetry = () => {
   const generationQuery = clientApi.assistant.getGenerationTelemetry.useQuery(
     { threadId: threadId ?? "", messageId },
     {
-      enabled: opened && persistedTelemetry?.provider === "openrouter" && Boolean(threadId),
+      enabled: opened && persistedTelemetry?.provider === "openrouter" && Boolean(threadId) && Boolean(messageId),
       refetchInterval: (query) =>
         query.state.data?.complete === false && query.state.dataUpdateCount < 6 ? 1500 : false,
       retry: 2,

packages/api/src/router/assistant.ts

@@ -738,7 +738,7 @@ export const assistantRouter = createTRPCRouter({
         }),
         getConfigurationAsync(ctx.db),
       ]);
-      if (!message) throw new TRPCError({ code: "NOT_FOUND", message: "Message not found." });
+      if (!message) return { complete: true, generations: [] };
       if (configuration?.provider !== "openrouter" || !configuration.encryptedApiKey) {
         return { complete: true, generations: [] };
       }

packages/db/migrations/seed.ts

@@ -512,6 +512,8 @@ const buildDemoWidgets = (appIds: string[]): DemoWidget[] => [
   { kind: "notebook", width: 4, height: 4, needsIntegration: false },
   { kind: "dockerContainers", width: 6, height: 2, needsIntegration: false },
   { kind: "weather", width: 2, height: 1, needsIntegration: false },
+  // Row 12: assistant
+  { kind: "assistant", width: 8, height: 4, needsIntegration: false },
 ];
 
 const seedDemoUserAsync = async (db: Database) => {