fix: handle missing message in assistant generation telemetry

getGenerationTelemetry threw NOT_FOUND when the stored message id did
not match a persisted message (e.g. the assistant message is still
streaming or was just removed), surfacing as a failed tRPC query in the
console. Return an empty complete result instead, matching the existing
graceful handling for providers without OpenRouter telemetry, and only
fire the client query once both threadId and messageId are 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: [] };
       }