changelog: add gpt-5.1 support

Author: hassiebp

pages/changelog/2025-11-14-openai-gpt-5-1-support.mdx

@@ -0,0 +1,20 @@
+---
+date: 2025-11-14
+title: OpenAI GPT-5.1 support
+description: Langfuse now supports OpenAI GPT-5.1 with day 1 support for the LLM playground, LLM-as-a-judge evaluations, and comprehensive cost tracking.
+author: Hassieb
+---
+
+import { ChangelogHeader } from "@/components/changelog/ChangelogHeader";
+
+<ChangelogHeader />
+
+OpenAI has released GPT-5.1, bringing enhanced capabilities and performance improvements to their model lineup. We're excited to announce day 1 support for GPT-5.1 across Langfuse's core features.
+
+Start experimenting with GPT-5.1 now in the [Langfuse LLM playground](/docs/playground), leverage it to power your [LLM-as-a-judge evaluations](/docs/scores/model-based-evals), and monitor usage with our comprehensive [cost tracking](/docs/model-usage-and-cost) capabilities.
+
+## Try it out
+
+- [Langfuse LLM playground](/docs/playground)
+- [Langfuse LLM-as-a-judge](/docs/scores/model-based-evals)
+- [Langfuse model usage and cost tracking](/docs/model-usage-and-cost)